In my experience, maintaining a very popular software library, supporting open source, and blogging have absolutely all contributed to my success, and, additionally, as someone who is now a founder seeking like-minded, highly skilled engineers, those are key signals for an attractive hire.

I can understand though, perhaps in a work environment where management is unlikely to be able to retain high skilled talent, you may want 'low-profile' workers that aren't going to have as many competitors chasing after them...