((I think, honestly, that the issue was stemming from the fact that I moved a bunch of threads over here from Tumblr and then replied to them because it was my turn-- essentially replying to my own posts, which wouldn't as a default notify anyone. LJ sends notifications when people respond to your entries and to your comments, and it does have a section in the account settings (under privacy) where you can set it to ping you when someone posts something with your user id. Beyond that, though... I dunno... Maybe the pingbacks just don't work on mobile.))