Yes, MyBlogLog has implemented tagging. Get all the details here, along with some thoughts from Mike at Techcrunch.
Nice job, Eric, Todd, John, Steve, Chris, Robyn, and Ian! (yep, that list is getting longer)
For now, I seem to own the tag “optimist.” I’ll take it!
Oh yeah, the team is hiring.
Chad Dickerson's blog 
saw that neat addition earlier today – though i was not the first cto tag – disappointing until i saw that the first was todd 😉