The Fat-o-sphere is a consortium of fat friendly blogs that cover various topics. 2007 was the year of the fat blog when the New York Times covered it. There are too many blogs to list, but here are some of the more popular ones.

Blogs
Big Fat Blog Big Fat Deal: Covers issues of weight in the media, pop culture, and society.
(Moderated, must be a member of LiveJournal): -- Chubby Chicks offers a safe space to learn how to be size-positive. Diet talk is not allowed.
The F-Word
: -- The best blog for fat news. This regularly updated blog discusses current news, articles and issues for the large-size person.
(Live journal) - All fat fashion, all the time.
Fat Rant
First, Do No Harm - Fat prejudice in health care
Health at every size
Junk Food Science - Rips apart myths about obesity and dieting.
Kate Harding's Shapely Pose
Pretty Pear - Lots of women of different sizes talking almost exclusively about clothes. Some topics discussed include finding plus-size Halloween outfits, sleepwear and hot new clothes.
Chubby Chicks Fatshionsta List of Fat Acceptance Blogs
Obesity Timebomb
The Rotund
suethsayings blog about dangers of weight loss surgery.
Well Rounded Mama (Plus size pregnancy)