Note: A more recent Software Testing top list is now available at testbuffet.com. Read this post for more details: Top 114 software testing blogs in 2014.
I ordered this list by gathering several metrics of each blog, to be more precise: the Google Pagerank, Alexa Popularity, Technorati Authority, number of comments and number of sites linking to it.(Note: Not all statistics were available for each blog. Where a statistic was missing, the blog in question simply scored 'neutral' for that statistic). You can read the algorythm I used to rank the blogs at noop.nl. Many of the results were gathered automatically using my Pagerank Checking script.
Enjoy the list and please let me know which blogs I forgot!
Edit: Meanwhile some kind people have submitted blogs which I did not take into account when I created this list. They will be included in future updates.
Test Side Story from Zeger van Hese would have been number 70.
Quality Perspectives from Lynn McKee would have been number 107.
Unimagined Testing from Nancy Kelln would have been number 90.
Software Testing Genius from Yogindernath would have been number 66.
Rob Kuijt's Testing Blog from Rob Kuijt would have been number 51.