The Techmeme Leaderboard lists the sources most frequently posted to Techmeme.
This particular version corresponds to the 30-day period ending April 20, 2010.
Sources are ranked by Presence, the percentage of headline space a source occupies over the 30-day period. "Discussion" links are not taken in to consideration here — only full headlines are counted.
An OPML file containing this list can be found here.
For more information, see this announcement