If you are the type of person who doesn't really care about the extra few 100$ on your tax return, never bothers to pick up your change, ... then this thread may not be for you.
Though if you are like me, like to pick up your change, try to ensure you aren't paying a fortune for petrol when you can get it 10c/litre cheaper 100m down the road, tries to pay as little tax as possible, and tries to get every cent for their work that they can ... then you just might get something from this thread.
Generally most of us aren't picking up all the income from our traffic that we can. I can be poorly disciplined at times and often I have to spend a week cleaning up my sites and ensuring traffic leaks are plugged, sponsors are working, and trades are up. I did one of these recently, and am already seeing a very nice little increase in weekly income. You add all those little $1-$.20 up over a lot of sites and you just might be surprised how much you have to show for it at the end of the year.
Many of us have over 200 freesites, 400 galleries, 20+ SE sites, a handful of portals, some blogs, and a whole heap of unfinished projects which are still getting traffic .. if only a little. And thats just from barely 1 year of full time webmastering... though some of us who have been here for much longer have more sites that we can remember!
You did the work, .... why leave money on the table?
Rotating Sponsors
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Sounds easy, but its a matter of maths and stats.
Personally I judge my sites and sponsor stats by $/unique impression. That means how many $ I made per unique visitor to my site x pages they visited. Its a no brainer to work the maths out for galleries etc, but for larger sites it can require a calculator.
I am looking for 0.2 - 0.3 cents per impression or one signup per 10,000 impressions. This can be heavily niche/site type dependant and on more niche like portal sites i am probably looking for over 1c per impression, and on some high volume low quality traffic types I might be giddy with 1 signup per 50k uniques and .05c per impression. So generally its only a guide, and you need to work out what is average and to be expected for you.
Work out the $ per impression for your site, break that down page by page, and then work out each sponsor's cost per impression for each page. In cases where you have more than one advert for the one sponsor on that page take into account the quality of that advert(position, size etc). I use a simplistic system, but I tend to divide all results by 2 in cases where I have one main sponsor on the page and several secondary ones. In some cases I will even divide ratios it by 3-4 which means that I expect that advertiser to do 3-4 times better when considering $/impression because of the larger banners and better advertising effort put into that sponsor.
Work out a system that works best for you, but when considering $/impression its silly to think that a 120x60 banner at the bottom of the page will pull the same clicks and $ as a 600x100 banner at the top of the page. You have to take into account the quality of adverts, and with experience this can be done just looking at the page and viewing the numbers in context. Sometimes a little system works best. This is the subject of another huge tutorial maybe someone else will do ... who knows.

So we have decided that sponsor A has to be rotated out because they are making .0000000003 cents per unique, and sponsor C & D are over .5c per unique. Easy

Why do we measure $/unique impression ???? Easy ... most sponsors dont count a lot of clicks, some only count 2nd page clicks, some join page clicks, some count 80% of clicks, .... hell i swear some only report clicks made on even hours, full moon nights, where the humidity is 30-40%, and the click comes from a url with the letters 'A', 'Z, and 'P' in it. who knows??!
... so the only two things you can rely on are your own server stats and how much money you made. Those are two reliable figures and not subject to others interpretation of a 'valid click'.
Things to look out for when rotating sponsors out using the $/impression value model..
1. A sponsor may have a low $/impression stat, but may be a secondary sponsor with a very low CTR (Click through rate). I consider a reasonable ctr to be around 2% for an average advert in an average location. Now if you have an advert with a low CTR .. lets say .5% CTR, yet your ratio for that sponsor is quite good ... lets say 1:500 on first page clicks and your $/click ratio is high, then you might want to see if you can improve the advert or give the sponsor a higher profile on the page.
2. If a sponsor has an average or high $/impression stat, but has a huge ctr of something like >8% ... though the ratio of clicks to signups is quite bad (say 1:3000+), and the $/click to sponsor ratio isn't that awesome ... say .5c/click, then it might be worth giving a high profile to another sponsor to see if you can preserve the ctr and increase the ratio or $ earnt per click.
3. Be careful you don't over-advertise a sponsor. Sometimes you can get better results from spreading the advertising around more evenly. Please be careful if using sponsor content or free sponsor hosting. Check first

Numbers Game
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This is a numbers game. Command your numbers, know your numbers, and make decisions based on numbers. Decisions should often not be made on who has the best looking affiliate area, who seems really cool, who flirts with webmasters ... its about numbers........ unless in Titanbuck's or NPC's benefit

Traffic ... more traffic .. MORE MORE!
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Traffic is king.
We all want traffic ... we need traffic ... we want more and more and more!! Did you realise that you probably have thousands of clicks of wasted traffic all over the place??!
Lets start with the basics.
.404/error trafficYou almost certainly have a whole heap of error pages, some broken links or some .404 traffic. I won't turn this into a technical thread, but a simple search on google or even netpond will turn up a whole heap of tutorials and links to setting up your .404 / error pages.
I will however touch on how what to do on your .404 page. Firstly I suggest against trying to sell full price memberships to class porn sites on there. I would try free email join sites, free CC sponsors, CPC payout sponsors (not many left though), or even one of the last few pay per impression sponsors left. CPC and free email join sponsors are what work for me.
Also ... don't be shy! In many cases a .404 page visitor is someone who has tried to find back doors into your site, or has edited your /gallery21/image4.jpg to /gallery22/image1.jpg or something to skip the advertising etc. Thats unless you just screwed up and left a link pointing to a page that doesn't exist (hey I do it all the time!)

In my opinion you hit them with everything you got short of installers and trojan crap. I hit them with popunders, popups on exit, free to join programs, special offers, fake members pages, pretend directory listings ... whatever.
My .404 page is my "I don't know how the hell you got here but now that you are here you are gonna make me some money whether you like it or not, or at the very least get me a visitor back through a blind link" ... page. I could probably write a 10 page tute on .404 pages and traffic management, but again thats the topic of another thread. Though let me say that your .404 page draws on your ability to filter traffic. Filtering traffic is a skill that isn't taught much anymore, but while it is a basic concept, filtering traffic is something that can take quite a bit of skill to implement well.
.404 traffic generally is totally raw unfiltered rubish, and you need to break it down in such a way so that the clicks are heading to places where they have at least a chance of signing up for a free join or entering their email. Also with many cpc payout programs they require that the surfer actually clicks again or does something on the landing page to count as a valid click and earn you a payout. Just sending blind clicks anywhere is a great way to earn bugger all

I have some sponsors which work well for me, but unfortunately I now keep my cards very close to my chest. They are fairly unknown and I like keeping it that way, however I am sure many people would love to spam their referral codes for some more known ones.

This brings me onto a side point ... sponsor research is essential. Don't just assume the most popular with the highest pps payouts are the best. You would be quite amazed at some of my stats, there are some really crappy affiliate programs with no webmaster tools who convert like crazy.
Without going into traffic filtering too much, and without going into which sponsors to use your .404 page is a page you should have a variety of easy to convert sponsors on there. Play with email join, free join, cpc, cpi, cpa programs. Have fun playing with your traffic
Image hotlinkingOh ahh ... someone is hotlinking your images. Well the best thing to do is get right into that .htaccess and change it so that they at the very least get a broken image. But why not throw up a small sized gif with your url on it and a little sales text. Many hotlinkings deliver several 10's of thousands of visitors to that image and a percentage will possibly type in your url. Free traffic

Though I am told more and more can be done nowdays with .htaccess and hotlinking, so I am sure if you look around you will work out a whole heap more nastly little tricks to pick up on their traffic. They are stealing your BW so why not
Some other trick[There are hundreds of other things you can do.... lets touch on a couple..
- Name your images well, add alt text and all the other stuff so that google images and other image browsing SE's pick up on them. Its not the best traffic but its traffic
- Instead of gallery1, gallery2, gallery3, ... try gallery1, g2, gallery3, or even just skip every 2nd/3rd one. Those sneaky surfers who try to direct navigate will feed your .404 pages

- Make sure you have a redirect or at least an index.html in each and every directory. You have no idea how many surfers try to find unprotected directories. Forward it to a .404 page or make up a nice clean fake 'open' directory page.

- If you have surfers from countries that just never signup, redirect them to pages with global dialer/global billing enabled sponsors. Some sponsors are able to make $ off even the worst surfers from countries that never signup for anything. All traffic can make you money. Don't only think that US traffic pays for porn.
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Trades/broken links
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I do this manually for the most part, but there are programs to do it for you. Go through and check your link trades, check your traffic trades and check your links on every page. You would be AMAZED how many programs and traffic trade schemes change their system or drop your link without telling you. You might be participating in a system like what choker used, and then realise that he changed his codes and you are sending traffic to his galleries for nothing. Keep your finger on the pulse!
Every click you send from your site is a click you have probably lost. Not to say you should be a mean old bastard, but if you are sending 100 clicks a day on a link swap, but only getting 1 in return then you have the right to bump their link down your page, or ask for something better, even though you aren't linking for clicks but for SEO.... it still pays to keep it in the realms of fairness.
Some tips
- Do you have a links page .. if so list toplists and traffic swaps etc on there aswell. chances are if they are on your links page they aren't interested in what your site has to offer and trust your site enough to have links to other good sites. Don't only list your link swaps, but throw up some relevant toplists and other links where you might get traffic back for clicks. Also throw up links to your other sites !!!!! Recycling traffic becomes a real money maker when you have a large network of sites!
- Every month have a list of traffic traders/programs/click trades/toplists that you go through and check. You never know when one of your traffic trade places goes down.... and having a master list can help you quickly and easily work out who went down and then all it takes is for you to go to the site they were on and remove them.... or follow up with them.
To finish up ...
you should not only spend the time on what makes you most, but make the most of your time spent.