Crossposted from Primer:
Advanced NFL Stats – More of a look at the game theory of football than a Football Outsidersesque stat site.
Cardboard Gods – Josh Wilker’s unique brand of nostalgia. Might be some existentialism involved as well (I was never good at philosophy.)
Driveline Mechanics – Batting and pitching mechanics
Evaluating Baseball Managers – Chris Jaffe’s publicity site.
Joe Posnanski – This one needs no publicity.
Prolate Spheroid – college football history.
Residual Prolixity – Posts from a Tennessee Titans fan that don’t fit his other venues. Only place I know that reviews old books about football.
Sabermetric Research – Phil Birnbaum’s frustration with academics who try to do econometric research about sports without understanding the sports they are researching.
Smart Football – Like Advanced NFL Stats only for the NCAA. Also shows a lot of charts and video of plays. Loves the spread offense.
That’s all the sports ones. I really don’t follow the blogosphere for much else; except the funny pages.