This is a good idea in some ways. I usually upvote my comments at a small percentage, but visiting their blog and finding a post you like and there upvoting it is a good idea! Sometimes I have lots of comments and it would take a long time to visit. Most of the time, my commenters are people I visit anyway. :) If you are a redfish still and don't have a slide voter, you can download a script that enables you to have it. This post talks all about it. It's great and enables me to at least give a tiny upvote to a handful of pepole. ;)
Sometimes it does take me a long time to circle back. Today will probably be one of those days... I enjoy it though :)