Franklin in Miami socks it to Michael Kimmelman and also has a post on the excellent Shambhala Sun - both posts are followed by lots of interesting comments. I hadn't known Bill Viola also spent time in Japan.
Artists looking to to be informed of opportunities should sign up for Michael Mandiberg's list. It gets e-mailed to you every month or so - a ton of stuff.
Charles Giuliano is a Boston based artist/critic/curator who e-mails a newsletter covering shows he sees, mostly in Boston and Western Massachusetts, sometimes elsewhere. To receive it, e-mail him at Charles.Giuliano@verizon.net.
Thanks to Perry Woodin at GalleryDriver for including anaba on it's artblog aggregator. They list a bunch of artblogs, showing what was updated most recently, saving you the time of having to actually go to each blog to see what's new. Franklin also has one - although it is a bit slow to load.
Lastly, Seattle artist Carolyn Zick's art portal isn't an aggregator, but it seems to be the most comprehensive listing of artblog links. Thanks Carolyn!