I love @pourmecoffee's list of canned replies to people on Twitter who "at" him with dumb responses to his funny tweets. One could use these canned replies for internet commentry in general, not just stupid people on Twitter.
# Please tell me more about how I might use my time and talent to perfectly match your unique sensibilities!
# I accept my (moral) (intellectual) (physical) inferiority.
# I acknowledge your (clever) (devastating) (hilarious) insult.
# I applaud your attempt to improve upon my humor (from an opposing ideological view) (with a slightly different twist).
# I stipulate that you are a very big deal online.
What's best about it: replying to the troll in question with just a number from the list, and a link. I may adopt this for daily use, myself.