There are already a bunch of well known "technologists" who don't just show up to do one Q&A session, but regularly participate in the community, which is, IMO, even better.
Not necessarily. On a site like this, where everyone has strong opinions on something, credibility matters. For example, I have only a rudimentary knowledge of programming, so when I read a post about JavaScript or something, I want to be able to quickly know whether the person is talking out of their ass or whether their opinion is backed up by experience and accomplishment.