STYLETHREAD -- LET'S TALK SHOP!

I don't use Twitter personally but I am in charge of it for my company. I'm still trying to get the hang of all the etiquette, though. If I do a search and I find, for example, that someone is asking a question that I know the answer to (whether it could be solved directly by our products or whether it's just something in our general area of expertise and we know the answer), is it OK to tweet at this person (who isn't following us and presumably has no idea who we are yet)? Or is that rude, like butting into a stranger's conversation on the street?