Why would you use anything other than AdSense if it's the most popular ? Well there are several reasons why you might want to try another network. Perhaps you had an AdSense account in the past and fell victim to one of their mysterious "invalid clicks" bannings, or you may want to diversify a bit. As my mother used to tell me, never put all your eggs in one basket.

Yahoo Publishers Network - http://www.publisher.yahoo.com - This is probably Google's biggest competitor. They offer contextual based text ads only. YPN is still in it's beta mode however and it's very difficult to get accepted into their program currently. At the time of this writing the YPN program is only open to residents of the US and they're still working on their ad targeting, it's not very accurate at times but this should be a very promising program once the work out the bugs.

Bidvertiser - http://www.bidvertiser.com - Another fairly well known name in the PPC game. Bidvertiser offers an easy sign up process, low payout threshold and quick ad setup. Their ads are not contextual in nature, but based on categories. If your website falls into the "shopping" category, you'll display ads related to shopping and the like. They offer category based text ads in various sizes.

Kirrhi PPC Network - http://www.kirrhi.com - A relative newcomer to the PPC field, but holds a promising future for a variety of reasons. Quick and easy registration, lucrative referral bonuses, nice selection of ad types, and a low payout threshold. Kirrhi offers contextual text ads in a variety of sizes, inline text ads, and personalized search portals.

Adbrite - http://www.adbrite.com - This one is a bit different in so much as advertisers can choose which publisher's site their ads are displayed on, and publishers can also refuse or accept those ads. This gives both advertiser and publisher greater control over the types of ads shown on their site. A very nice feature if you ask me. Sign up is fast and painless, ad types consiste of contextual text ads, inline text links, and interstitials. Low payout threshold also makes this an attractive choice.

Kontera - http://www.kontera.com - This program takes advantage of the inline text ads. Simple to integrate and it's a setup and forget about it kind of system. Very easy to use and register. Net 60 payout terms and $100.00 payout threshold may make this one a bit undesirable for some publishers.

Alternate URL - http://www.alternateurl.com - What started out as a means to fill up those PSA ads with AdSense has morphed into a very nice PPC Network in it's own right. Registration must be approved and takes about 48 hours, but it's well worth the wait. Alternate URL uses context based text ads only, but it's definitely a very nice program with great earning potential.

As you can see there are many alternatives to AdSense now, you're not restricted to just one PPC Network while trying to monetize your website's traffic. Our list is by no means a complete list, but it should be enough to get you started on the road to life outside AdSense.