It seems from reading SO that there's a lot of legal concern about Boost in some companies. Some people are apparently prohibited from using it. Since Boost is licensed under about the most permissive license you could possibly think of, where does this concern stem from.
Edit: People have asked for specific posts. I don't remember where these were, but the reason I'm asking this is because in the context of these posts, nobody detailed the concerns. People just said stuff like they're "not allowed" to use Boost, the implication being that it was for legal reasons, w/o being more specific.