I've been working in multiteam groups for as long as I'm a webdeveloper, for me a team can be a lonely soldier or several people, generally a company will have multiple teams working in different projects and once the project is out in the wild, any team can perform the maintenance.

This is a small picture since I'm not talking only about project wise knowledge, but "craft wise" knowledge, but it gives the picture of how I'm used to work, so:

Since we work on modularised teams, sometimes I feel like the teams are too tightly enclosed in their projects, I've seen cases where after an hour of discussion, someone asked the question aloud and other person totally unrelated answered in a much simpler fashion.

The problem is not so simple to solve as people tend not to be available all the time, also sometimes people can't afford the time to go through a problem with the "asker", but could do it alone.

I've thought about software based solutions, something in the lines of SE, but I'd like to know other programmers opinions on the subject.

EDIT

I don't know if this is a wikipedia complex, but I feel that Wikis don't encourage the user to actually ask questions, but rather to write articles, and sometimes we don't know the knowledge we need, before needing it.