"Show me the money. " That is the web 2.0 slogan as few web 2.0 sites have been able to generate revenues to break even.

This story is In two parts:

Part 1: Sources of Revenue

1. The Pagerank model: Sites or pages with greater pagerank will rank higher in Google search results and thus more opportunities for Adsense income.

2. The Long Tail: Let users come, submit and create content on all topics and we will make the money from Adsense on any topic. Everyone is doing the same so now there are more publishers than Long tail topics.

3. Advertising: The only working model (using banner ads, which are good for branding purposes) but barely. CPM rates are abyssymal. Adsense, the contextual advertising is no better. Varieties include in-text contextual advertising, which always annoy users. RSS ads are also happening.

Part 2: Web 2.0 ideas

1. Affiliate Networks and Affiliate Programs - Taking a cut from brands based on sales/action taken - cost-per-action (CPA). Very often, the money is made by generating leads through inquiry forms. Example: Linkshare, Commissionjunction, Clickbank, Amazon etc.

2. Paid blog post - A controversial area. The blogger's reputation is affected. e.g. reviewme.com, payperpost.com

3. Premium Content - e.g. paid reports from Paidcontent.org, Gigaom.com; subscription only newspapers - FT.com, WSJ.com, Economist.com

4. Selling Tags and Keywords: High Traffic Sites can use this strategy by credibility is suspect afterwards.

5. Selling Virtual Goods: e.g. Facebook Gifts, Second Life Currencies, WorldofWarcraft things etc.

6. Ad Networks: e.g. Glam.com (centeredt around women-focused sites)

7. Blog Network: Creating the blogs' equivalent of a newspaper. e.g. Gawker, Webslogsinc etc...

8. Content Network: Network of sites, sub-domains for reference content e.g. About.com, Hubspot.com, Squidoo.com, Mahalo.com

9. Blog Aggregation/Blog Search: e.g. Sphere.com, Technorati.com, blogsearch.google.com

10. Buying and selling domain names: Profiting for demand by marketers to set up websites around keywords.

11. Competitive Intelligence: Analyzing internet usage and selling reports and stats e.g. compete.com, Hitwise

12. Bookmarking: A very competitive area dominated by Del.icio.us which started the idea.

13. Social News: Another competitive area dminated by Digg, Reddit and Propeller.

14. Feed Aggregation: An area dominated by Google Reader and Bloglines.

15. File Sharing: P2P business. More disruptive than revenue making so far. e.g. Bittorrent.com

16. File Uploading: The unsung hero. Dominated by Rapidshare.

17. Hosting Open Source Projects: Dominated by Sourceforge.net and Google Code

18. Technology Conferences: Many made money from it including Demo. Now, under pressure during recession.

19. Internet radio: e.g. Last.fm and Pandora. Always under legal pressure from the music companies.

20. Internet TV: e.g. Joost (P2P) and Brightcove.Now, the trend is towards TV companies doing their own thing (Hulu) or working with Biggies (e.g. Youtube)

21. Internet video: Dominated by YouTube. Gets you traffic but where is the money?

22. Job boards, Job search and Job Social Networks: (job sites) Monster, CareerBuilder, Dice, Naukri. (Job search engines) Indeed, Jobster and SimplyHired. (Career Networking ) LinkedIn.

23. Mashup: Most famous example, http://www.housingmaps.com, real estate listings from Craigslist + Google Maps. See more on http://www.programmableweb.com/popular.

24. Massively Multiplayer online game: E.g. World of Warcraft, Guild Wars and Lineage.

25. Mobile social networking: The next big thing.

26. Music distribution site: iTunes dominates this space.

27. Online Advertising: Can you compete with Google Adsense or Yahoo Publisher Network?

28. Online auction: The charm is fading. e.g. eBay, Overstock.com and Amazon Auctions.

29. Online classifieds: Dominated by Craigslist

30. Online surveys: e.g. Polldaddy, Survey Monkey.

31. Open source: Create a free web 2.0 site creator e.g. wordpress.org and make money from consulting and support. In case of Wordpress, third party developers sell themes and make money.

32. Outsourcing marketplaces: A step up from classified sites. e.g. Elance, Rentacoder and Guru.com.

33. Online Payments: Can you compete with PayPal and Google Checkout. The trend is towards mobile payments.

34. Human-powered Search: e.g. Mahalo, Chacha.

35. Personalized start page: One stop aggregator sites e.g. Pageflakes, netvibes or iGoogle. An example of feature-only web 2.0 offering that any big fish can copy.

36. Photo sharing: Can you compete with Flickr, Photobucket or Imageshack?

37. Real estate: Under presure during recession. e.g. Redfin, Trulia and Zillow.

38. Recommender system: e.g.Pandora (music), Netflix(Movies), StumbleUpon (links), Last.fm (Music)

39. Search engine: Google still can't do good blog search. Searching across social neyworking and bookmaking sites is still unfinished. But, you need resourecs and great programming talent.

40. Selling content digtally: e.g. Sell ebooks or t-shirts through Cafepress (anything), Lulu (books)

41. Social networking site: This one generates the most number of copycats. Dominated by Facebook, Orkut, Myspace and some others.

42. Software as a Service (SaaS): Hosting business software on a server and offering subscriptions to businesses. e.g. Google Apps Suite, Salesforce.com, Microsoft Office Live, Microsoft Windows Live, Zoho Office Suite, and 37Signals products.

43. Travel site: Dominated by Portals such as Expedia and aggregators such as Kayak.

44. Vertical search engine: e.g. Kayak.com (Travel Deals Search).

45. Virtual worlds: Social Networking through digital personas. e.g. Second Life, Habbo, Gaia Online and There.

46. Voice over Internet Protocol (VoIP) sites: Once, a very hot area. A lot has changed after the Vonage story. Most famous example: Skype

47. Web Analytics: An area dominated by multi-featured free software. e.g. Google Analytics, Statcounter, Sitemeter.

48. Web and mobile messaging: Meebo is the best service that allows users access to different messaging platforms through a single interface.

49. Web Conferencing: At its simplest, Campfirenow from 37signals that allows members of team to chat.

50. Webmail: This area is still promising. But can you challenge Gmail, Yahoo Mail?

51. Wiki: Getting users to pay for creating wikis is tough. Only a few including pbWki are attempting it.