Drew Meyers wrote a great vision piece on how Web 2.0 will develop before it evolves into Web 3.0 (say, Web 2.5). His main points (as I see them, hope I'm summarizing Drew's vision accurately) :

(1) "Blogs will become a person's online profile". And the blog platform may soon serve as the "all-in-one portal", incorporating personalization and social networking functionality. (2) APIs will facilitate the personalization of these all-in-one portals - although technically incorrect, I think of APIs as widget builders. (3) Wikis will become more powerful , but sporadic user contribution is an issue. (4) Mobile apps explode - a given, we already see their power in the countries like Korea and Finland. (5) RSS feed search - query on the sites you subscribe to... sensible search functionality.

I have only one comment  - Wikis will become more powerful when it demands user contribution. Wetpaint is a great all purpose wiki product where the owner defines a compelling wiki utility (it may be just an update-able college party calendar). I go on record two times saying the authoritative Wikipedia-type wiki doesn't invite a lot of contribution.

I have one more observation based on some hands-on experience the past week - Meebo and other real time chat products is a killer app, especially in the lead response time sensitive real estate industry. A potential client can communicate with a quick "hi" in the chat box and the dialogue begins... it's anonymous until an introduction is finally made based on the tenor of the dialogue. Right now, most people are reticent to start cold chats. I think the attitude will warm up. The evolution of the internet is advancing open communication - from email, to MySpace, to blog commenting to social networking in all forms... the societal sea change towards online openness will soon make typing "hi" into a chat box as common as writing a journal entry in Facebook.

The point - It's amazing how simple the chat box concept is and how it has been overlooked by online real estate as an instant lead response tool for as long as it did. Chat was one of the internet's first big hits (remember ICQ when it came out?).