There are several ways you can earn money from advertising:
1. Join an advertising network. Advertising networks are organizations that aggregate Web sites that offer advertising space, and sell banner ads (and other advertising options) across them. Traffic requirement is often a minimum of 5,000 monthly impressions, although many do not accept sites hosted by free page services.
Burst Media http://www.burstmedia.com
Fastclick (ValueClick). http://www.fastclick.com
Advertising.com. http://www.advertising.com
Tribal Fusion http://www.tribalfusion.com
2. Participate in contextual advertising networks. Contextual advertising are text ads delivered based on the content of the web page using an automated system.
Google Adsense https://www.google.com/adsense/
Yahoo! Publishing Network (currently in beta and available to US publishers only) http://publisher.yahoo.com/
Intellixt http://vibrantmedia.com/site/web_01a5.ht…
Quigo Adsonar http://www.quigo.com/adsonarexchange.htm
IndustryBrains http://www.industrybrains.com
Commission Junction Evolution http://www.cj.com
Kanoodle Brightads http://www.kanoodle.com/about/brightads.…
Clicksor http://www.clicksor.com/affiliate_progra…
Contextweb http://www.contextweb.com/
Bidclix http://www.bidclix.com/
Bidvertiser http://www.bidvertiser.com/
3. Sell advertising for your site directly. This is admittedly a more difficult route for a small business site wanting to earn advertising revenues. But hey, as they say: “no pain, no gain!”
4. Affiliate Programs – you sell other people’s products that your audience may be interested in; and you get a certain commission after the desired action was done (whether a sale, a lead, subscription to email newsletter, or however this is defined)
Commission Junction http://www.cj.com
Linkshare http://www.linkshare.com
Clickbank (for ebooks and digital products) http://www.clickbank.com