For those who use public transit, anki on the phone is lifechanging. I'd advise keeping a small notepad with you in case you think of something to look up, check, add or edit later - those are all inconvenient on the phone, especially if one is on the subway and can't get online at all.
I use Notes on iPhone to record things to look up, check, add or edit later.
This is the public group instrumental rationality diary for July 1-15.
Thanks to cata for starting the Group Rationality Diary posts, and to commenters for participating!
Next diary -- July 15-31
Immediate past diary -- June 1-30
Rationality Diaries archive