While Mrs. Atrios obviously shares a pseudonym with me, she didn't share a last name. We didn't think much about this when we got married - there were a few purely practical reasons it was easier for her to keep her name - but it seems perfectly normal. Normal, at least, until we realize that for a lot of people it's a freaking weird thing to do.
Anyway, I don't really care. I can understand reasons why people share names, and reasons why they don't, but again, who cares? It just isn't important.