Memes are great helps in judging the effect a story has on the blogosphere. Some index all content that it sees, some only index a finite listing, and some do a combination of the two.

An early adopter of Memes, Richard MacManus of The Read/Write Web, has put together a comprehensive listing that’s a great overall view of some popular or start-up Memes. Of course, he’s a little biased towards Memeorandum because he is a friend of the creator, but he’s transparent about that fact.

Use services like TailRank and Memeorandum to get a pulse of what is currently hot, in the blogosphere.  PR bloggers and anyone interested in online marketing can benefit from this real-time market research.