have been writing about Web 2.0 in this blog and I know that some of you have heard about Web 2.0 and would like to be involved with it but do not know where to start. When you look for "web 2.0" in Google 168,000,000 results will come up. If you look for "web 2.0 and medicine" 4,730,000 results will come up. This huge amount of pages that talk about Web 2.0 makes difficult to know where to start. That is reason today I will leave here a small list of Web 2.0 directories. Personaly I use Go2Web20, you have to pick the tag that best describe what you are looking for, and all the pages that are related with this tag will appear.
A tag is a (relevant) keyword or term associated with or assigned to a piece of information (e.g. a picture, article, or video clip), thus describing the item and enabling keyword-based classification of information.(Wikipedia)
Remember that "tags" are really important, we the people tag the pages, not the programmers. That is an important difference in comparison with the old web. I consider that this is a feature that make the Web 2.0 so powerful, because is the people who feed the web with their ideas.