Well, wonder no longer! I have been doing some careful research on this very topic, and I have all the answers.
- 15% of the people who have you friended have since left for greener fannish pastures, or perhaps for somewhere outside of fandom altogether (it's sad, but it happens; fannish scientists are working round the clock to discover a cure, except for the four hours they spent reading that Jack Harkness/Brian O'Conner epic last night). They no longer read your fandom-related posts. (Or, alternately, it's cats they don't like. My point is: whatever you posted doesn't interest them.)
- 15% were planning to get back to that post later. It's open! It's in a tab! Or it's in Read Later! Just...wow, busy, you know how it is. (Of course, if you're counting every comment and comparing it to a master list, maybe you don't know how it is. In that case you'll just have to trust me.)
- 10% of the people who have you friended think you're boring. (Sorry! Sometimes science means having to say the hard truths.) They scroll past you, or they filter you. Or maybe they think everyone they have friended is boring, and they don't read their friends list at all; their friending is just a social nicety. It would probably be better if you believed that last one. Yeah, this segment is the one we'll call "social niceties."
- 10% of the people who have you friended weren't reading the day you posted. Someone had horrible news and came home and went straight to bed with a dog and a hot water bottle. Someone has food poisoning and is puking too much to go near her computer. Someone is addicted to a flash game and can't click away until she beats level 77. Someone is in the South Pacific having a lot more fantastic sex than you ever have or ever will; she isn't thinking about you or fandom right now. (Okay, she's thinking, "I have to use that the next time I write Merlin/Arthur, or John/Rodney, or Bertie/Jeeves - ooo, yeah, Jeeves is probably mega-kinky." But she's not missing her friends list, is my point.)
- 10% only read you on a phone, or a netbook or internet tablet that's impossible to type on, or a Kindle, or in five minute snatches at work or between dragging kids to soccer or whatever. They love you, but they never do manage to get back to comment.
- 10% of the people who read you only lurk. They lurk everywhere. Maybe they can't type. Maybe they have tentacles and can't find a tentacle-ready keyboard. You don't know. And do you really want to risk displaying your prejudice against the betentacled?
- 5% of the people who read you are still pissed off about the comment you didn't reply to. You know the one. (You reply to every single comment you get, you say? Even the ones obviously from bots? Even the ones LJ forgets to notify you about? In that case, these people are sulking about an inadequate response you left them, where you missed the point or missed the question or failed to thank them or sounded snarky. You can't please everyone. Not even with an incredible facility at hitting "Reply.")
- 5% of the people who read you are still pissed off about that post you made. You know the one.
- 5% of the people who read you are pissed off that you didn't comment on one of their important posts. They're withholding sex - sorry, I meant comments - until you understand how important they are, and maybe send some flowers or something.
- 5% of the people who read you have broken internet connections right now. Fucking Comcast.
- 1% of the people who read you hurt their hands this morning.
- 1% of the people who read you currently have a broken spacebar.
- 1% of the people who read you are heavily medicated. Their loved ones have taken away their keyboards for everyone's safety.
- 1% of the people who read you are seriously undermedicated. Their loved ones have taken away their keyboards so they still have friends when the meds kick back in.
- 1% of the people who read you read you in bed, and a loved one has threatened to take away the keyboard if they type at night anymore.
- 1% of the people who read you are sockpuppets. They're only going to comment if they want sparkle pens.
- 1% of the people who read you are, in fact, commenting, but they're doing so by telepathy. If you're not getting the comments, well, obviously something is wrong with you. They can't be held responsible for that.
- 1% of the people who read you are aliens. They can't ever pass the prove-you're-human test, and for some reason they get the CAPTCHA every time. They are thinking of filing a lawsuit against LJ.
- 1% of the people who read you cannot comment for religious reasons.
- 1% of the people who read you haven't figured out that you have to hit the "Post comment" button in order to get the comment posted. They keep typing like it's an IM box, and nothing ever shows up, and they just do not know why. They've submitted several complaints to Support about this. (It's possible you didn't want to read their comments anyway.)
You're right. It is. So, hey, if you get any comments at all, you have beaten the odds. You must be really awesome and special. Can I friend you?
(P.S. I don't comment a lot, but I'm probably reading. And I'll repeat what I said in my info: I love all the comments I get, except the ones from the spambots who are cordially invited to DIE DIE DIE, but no one ever should feel obligated to comment here. I get the lurking, I really do.)