From the Home page here at LJ. Like we generally tend to read there! I certainly don't as a rule! (grin)
Update: Many people are asking about the delayed comment notifications over the last few days.
We used to have 2 email servers, even though we only needed 1. Then 1 blew up the other day, and the 1 surviving one wasn't enough to keep up with all the email and got behind.... so now we have 3 mail servers online, but that one burdened one is still catching up, sending out many-day-old mail. You'll continue to get old mail for a while, but it should catch up soon. We're going to be redoing our mail architecture, though, after seeing how easily our existing setup died.
So now we finally know the 'official' answer! LOL.
I'm still getting comments now from days ago, personally. (Which seems like more than a one day lag, but why bother counting, I guess...)