Free web service BackType aggregates all the comments you make on various blogs and web sites. The site uses the URLs entered in commenter forms or in the posts themselves to track a person's musings, or can combine URLs under a single account URL. It's a great tool for those who want to catch up on discussions they left behind, but the site also provides a search engine of its indexed comments and links to see another social-browser's comments. This type of URL tracking would normally leave the door open for comment impersonators, so BackType offers a moderation option to have you approve any comments posted under your name. BackType is a free service, requires a sign-up to use.