fav.or.it API

From their site: The fav.or.it API allows access to many of its core services. The first round of exposed requests allow comments to be distributed from external clients through fav.or.it back to the host of the specified blog. Suggested uses: Give commenting functionality to PC/Based RSS Readers; Extending web based RSS Readers; Send comments from embedded widgets; Supply comments from external blogs. Services that can be authenticated with fav.or.it currently: openid, twitter, blogger, wordpress, and bloglines.