My other blogging activity, on the increasingly rare occasions when I post to it, is on Dirac Angestun Gesept, also known as dirac_angestun. If you're friending me to see what I'm up to or what I'm writing, you may also want to friend that.
My LJ tends to have more "what's going on", while I'll put "think pieces" or pointers to code I've written or whatever over on dirac_angestun. Things that I expect lots of comments on will usually wind up here, since LJ handles comments better than Movable Type does (threading, etc).
The term "friends" has enough additional connotations that I'm trying to consciously avoid using it in ways that imply things that aren't there. I will therefore refer to my "flist". (Hey, it could be worse: I considered calling it the combined regular read/access list, or CoRRAL. Yeah.)
You're on my flist because I want to read what you post (or want to read what you would post if you ever posted), and/or because I want you to be able to read my fairly rare locked posts.
You can add me back if you like, or not; I won't be offended. Reasons to add me: you want to read my posts and/or you want me to be able to read your locked posts. If you use opt-in filters for subsets of your LiveJournal, please let me know what the options are.
I may remove your LJ from my flist, or move you off my default view, if I feel like I'm getting overwhelmed. It's not personal, I don't hate you, I just may not feel like I can read your LJ right now for whatever reason (time constraints, personal issues, RSI flareups). My Default View filter is public, so if you're wondering whether or not your LJ is on it, you can check.
If you have no idea who I am, and wonder why I added your LJ to my flist: it probably seemed interesting at the time.
Possible ways I found your LJ in order to find it interesting:
Comments you posted on an LJ I'm already reading
You're on a friend's friends page, or multiple friends' friends pages
Pointer to an interesting post on your LJ from someone on my flist
USENET .signature or other pointer to it, or some other way I associated someone I remembered from USENET with your LJ. If you were interesting there, I probably figure you'll be interesting on LJ too. (Someone, can't remember who, said that in USENET terms, an LJ is really "alt.fan.me.moderated".)