There's some interesting way stations in the Seattle blogosphere and a surprising amount of long-standing blogs.
There's the Seatown Mariners - two guys who occasionally write about the team. The Mariners communication dept keeps a daily blog with game information, promotions and articles from the official magazine (FO take note!). There's a website that covers all Seattle sports - here's the Mariners section. Mariner Central is a discussion board in the SOSH mode but not as entertaining. Seattle Mariners Musing started in 2005 and just retired 6 weeks ago. Evening Perambulations started in 2004 but gave up the ghost in last year.
One of the amazing things is how long there's been one-women blogs. Compass Rosy started in 2009 when Ken Griffey Jr re-signed with the Mariners and she still posts fairly frequently. Section 331 goes even farther back to a live-journal started in July 2008 - it's now a WordPress blog.
If you're really looking for the defining characteristics, you're looking at two blogs:
Lookout Landing
Jeff Sullivan founded this blog in 2003 and it became one of the first in the SB Nation network in January 2005. He ran it for a decade until Fangraphs came calling. One of the most respected fan blogs in MLB. It's the only SB Nation blog I've seen that keeps a list of other team blogs. There's a great section that Jeff created called Raul Ibanez Takes Pride in his Defense and it's as funny as it sounds. There's a section on team history. There's a podcast. It has a reference section not just for their own culture but for any type of analysis you can think of.
Recent "satire" post: A Viewers Guide to Hating the Toronto Blue Jays
USS Mariner
It's not surprising that Jeff Sullivan got hired by Fangraphs because this site was co-founded by Dave Cameron in 2002. It's even more stats-oriented than LL. They have a suggested reading list that encompasses not just stats but strategy. One of the co-founders, Derek Zumsteg, even published his own book, The Cheater's Guide to Baseball. At this point, the site is predominantly game threads but it still has a loyal following.Recent post: Game 150: Blue Jays at Mariners