Squidoo, a knowledge sharing community, looks cool.

It features the common tagging system. Users after signing up could create their own 'lens'. In lens you post tips in the domains you are good at.

Quote from Squidoo's faq:

A lens is one person's (lensmaster's) view on a topic he cares about.

It's like personal yellow page used to record information. Although sounds it the same with other existing on-line information management applications, it intends to become a knowledge sharing community. Using ranking and tagging system, making finding popular or specific lens possible.

Squidoo mentions "a co-op of experts". I think that's an exact description of the model Squidoo wants to be. According to their statement, Squidoo's profit model is to gain traffic as more as possible. And those traffic come from the attractiveness of the people they call "lensmasters". Lensmasters are a group of experts with strength of specific themes.

The combination of Squidoo and blog may be a good experiment. To start a blog is easy, but not always for promotion of a blog.