"Random Trivia" is just what it sounds like, a catch-all for updates, anecdotes, and so forth.
"Life" tends to include posts that are a little more introspective.
Posts relating to a certain person are now tagged with the inital letter of that certain person's name. (It falls somewhere between "F" and "H" in the alphabet.)
Current events (international and domestic) are under "World", except for Iran which gets its own tag. Jewish-related stuff is under "Hebraica". Obituaries and memorials are under "STGM" ... if you're a Latin geek you can probably figure out the abbreviation.
"Friends" refers to friends in general, LJ and non-LJ alike. "In Pro Per" (more Latin!) is for those all-too-rare occasions when I get to meet LJ friends in person. And TNG ... well, TNG needs no introduction.
I've also modified the visibility on a few old posts, generally in the direction of more openness. As you know from my userinfo, I like to write open posts as much as possible and I'll only friendslock when the stuff is unusually personal, or when another person's privacy is involved.