Good one. I always tried to answer people who commented my posts at first, because its common decency. But after a while i realised alot of the comments were just spam. Now I always answer real comments AND upvote them - while ignoring the spammers/beggars. We have to encourage the behaviour we want to see!
Absolutely - I also tend to upvote good comments.
Am surprised the good people on this whole thread do not upvote each other more. Sometimes, we may write on very different topics so it is good to see new usernames on a theme that unites us.