In the next 24 hours UK feed-reading and commenting aggregator Fav.or.it plans to open up its API to allow anyone to send comments to any blog in the world. Founder Nick Halstead told me via public Twitter that he was “exposing the API for the first time so developers can get going” prior to the full launch of the service. The startup is still in closed beta. Favorit’s key functionality creates a single platform that aggregates blogs and allows you to comment on blogs without visiting them. It then analyses that attention data and suggests relevant content, in theory increasing readership for related blogs.

Fav.or.it won angel seed investment in December 2007 from UK angel David Richmond, who also joined the board. Richmond founded Striva Corporation in 1998, which was sold to Informatica Corporation in 2003 for $62m. More recently he has also been executive chairman of TouchClarity, acquired in early 2007 by Omniture and CEO of Red-M.

Here is an interview by Robert Scoble with Halstead, an indication in itself that this is a startup to watch.