lucy24 - 10:21 pm on Jun 22, 2013 (gmt 0)
Blacklists are useful for keeping out stupid and lazy robots. But keep the list short. Last time I looked at mine it was somewhere between 20 and 30. Just the no-brainers and the ones you find personally offensive.
Whitelisting by itself doesn't do much for the robots with humanoid UAs. (Has anyone ever figured out what the plainclothes bingbot is for? It isn't translation, and I'm not prepared to believe it's just ms employees on their lunch break.)
The number of genuine human cell phone user-agents appears to be infinite.