Background
There are now so many banner exchanges it can take a while to choose which one is right for you and your traffic.
This Page is designed to help you through the process of choosing your banner Exchange company.
It used to just be that all the Exchanges would offer a 2:1 ratio (for every 2 times someone views a banner on your site, your banner is shown once on someone else's) So it was just how many Extras you got, know you can get ratios up to 5:4
There are new exchanges released the hole time and I will make sure that they are included here

Ad-Exchange or Referral
What would you prefer, others to see your banner or money? If you want money then you normally get money per sale or click-through, (like a percentage or commission) or if a guestbook or Feedback form is filled in.
If you want an Ad-Exchange then this is done on a ratio basis as described above

The problem with referral programs
Most referral programs have minimum pay out fee, and this is what to look for When choosing your referral partner. How much per clickthrough? Some only offer $0.02 dollars per click through some up to $0.46, both these examples are from clicktrade. But they may well have a minimum of $20. Turbocom.net does not have a minimum but they pay a (nice) commission not per click-through I think they are the most advanced and if you are a member of Multi-Exchange or Traffic X you may well have their button on your site anyway.

Prioritys; High ratio or Extras/perks?
If you chose an ad-exchange program then the main Question is what do you think is more important, a high ratio or better stats? But remember you can get stats free from someone like EXTREME TRAKING but if you want the sort of tracking you get from LE, being full site/ multi-page results they do charge (even if it is quite cheap). N.B you may be able to get good stats from your ISP (Internet Service Provider)

What size: Banner, button, board or link?
Though many offer both this is still important, especially if you have a really nice graphic of a spesific size. The common Banner size is 468*60 and buttons are about 31*88

Now you have got your preferences its time to choose your network.
The specs for many Exchanges are on one page. The quick reference below for more information on the biggest best and most popular ones

ClickThru Network	This is a very good deal, 1:1 click throughs. You can get credits from going to other members sites (by clicking on the click-thru logo) or by sending other people to a members site with a banner or the ClickThru Network Random Link
Multi-exchange	Best for ratio, 5:4 instead of 2:1 which makes a big difference. Plus you can have more than one Button/banner, and you get 300 free hits when you join. The code they give you can also be changed on each page, which suggests that they will soon be doing the same stats as LE. If they do they will be by far the best.
Link Exchange Deluxe	Best for stats, you put a slightly different code on each page so that you can see which page has the most Hits. You have a list of your pages and the amount of hits they received
Traffic x	Best for Guaranteed traffic, rather than how many times an advert is seen this is done by how many times the advert is clicked on. With a 2:1 ratio, this has worked out very well for me as lots of people have clicked on buttons on my site which also suggests that the sites on this network (or at least the buttons) are good quality. It is likely to work out well for site with low traffic as well as they guarantee extra traffic in the first month otherwise you get 10 credits which, means 10 hits
Bottom dollar network	This is another unique Network they say you will get extra traffic and money. But it doesn't quite work out that way, I got $0.67 for having it on my site which is not enough to qualify. Even though quite a few people used it. I would not suggest putting them on a page with many hits, maybe put it on a separate page (I moving it to the search engines page) this way it is treated like a resource rather than an advert. Most Networks will carry your balance forward but BDN do not.
	Have you seen the little clicktrade logo on any sites? If you click on it, it goes a list of the pages the link to the site you were on. It also gives you the option to link to them and tells you how much you will get per click through. This is a very good service but you have to find the right the site to get the most clickthroughs which could take some time.
Registar-it / Web site garage	Yes these 2 companies share the same program, which is useful as it, makes it more likely to reach the minimum amount required. But on the other hand they work on a commission basis and though there service is very good (especially website garage) they offer free versions of there service which are almost as good. So all I have got for being a member is an E-mail each month saying "you have earnt $0.00 this month" But this is also a resource so if you treat it as one rather than an advert it doesn't matter as much
New exchanges	New exchanges have to be good and offer something new or they will not work, Both Traffic X and Multi-exchange are new and both offer unique services. I'm sure somebody will copy Traffic X's idea with a better ratio like 5:4