If it is a nice email well thought out and they have "read my profile" then yes I will respond with a nice email.

Most of the time They don't read my profile just look at pictures

Sometimes yes, sometimes no. It depends on my mood, on how many fake messages I had that week, and various other things.

The less thoughtful the message is, or the more off the wall, the less likely I am to respond.

I wanted to be one of the "always answer" people when I first came online, but that proved to be a mistake.

And for absolute certain, if someone sends a nastygram follow up to a message I happened to miss, or didn't respond to, they will REALLY go in to the discard pile.