What about the site makes it most addictive for you?

I think its because its so dynamic. I am always on here seeing whats new or what changed. It also helps that I am really interested in the content on the site

The relevance of the content--its startup-centricity.

The site has great value for the entrepreneur with both the content and the people posting - a winning combination. (I also admit to checking multiple times a day - usually between hard coding or architecture problems)