Here's a sampling of the best in my RSS reader:
gwern posts on google+ and Kaj Sotala posts interesting stuff on Facebook. I also subscribe to a number of journal's table of contents via this site to keep up with research and some stuff on arxiv.
I have to admit the intersection with my feed list is most definitely non-empty: I'd add Good Math Bad Math, mathematics, computer science and, sometimes, recipes and playlists.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Duration set to six days to encourage Monday as first day.