Wow, great thread!
I met a lot of people online, made quite a few friends, got reacquainted with an old friend from Middle School that moved out of state and we lost contact, and then also got out of touch with online friends as well.
What happens, unfortunately, is "life", plain and simple. A person may be inbetween jobs, or have extra free time, and may have a lot of time to spend online and in the process of course, makes friends. Then, life hits- a new job, school, a marriage or separation or divorce... and all of a sudden there's not much time to spend online any more. Maybe they have to drop their internet connection, or they move and it takes awhile to get back online...and by that time, email addresses or site addresses are lost, online nicknames change, etc.
Other times, maybe things change site-wise. I was in a club on MSN awhile back, and we had to make it an "adult" club in order to keep it a private club, because at that time there was a lot of hassle between rivals. It was a musician club, but there were a lot of idiots on our main site, AcidPlanet, as well as rival clubs. Anyhow, MSN decided one day to drop their clubs, and gave everything up to a rather slow host with a poor server or something... people had a hard time getting into it, and some that were unfortunate enough to be stuck with dialup server couldn't get in at all. The club fell apart not long after. Everyone drifted their own way, and even drifted away from AcidPlanet. I still rarely stop in there, and as I have no time to make any new tunes, I think I posted one song a couple years ago, and that was it.
Internet friendships are very hard to keep, because realtime life keeps interfering. If people lived closer to each other, and/or if there was more time in a day (lol!) it would be easier to stay in touch. Makes it even harder when people have a lot of interests and are on several sites instead of one or two main ones. If you are able to keep one or two friends you meet online, you are extremely lucky, IMO. Personally, I do my best, but it gets hard sometimes. There's only so many hours in a day, and so many days in a week. I have to divide it between school, family, pets, house and yard work, homework, real-life friends, eating, sleeping... and then online I have to divide my time and stop in at my own site at least once in a while to see if anything is going on that needs my attention. I'm kindof a senior staff member, but am never there any more... and I don't want to lose my Ban Button, LOL! I just love putting the smackdown on spammers! :D
None of this is an excuse or anything...just kindof what I have seen and lived online the past 10 years. As for my own real life, I have been separated twice (together again, now), both daughters have had serious medical emergencies on more than one occasion, I have moved a couple times,I have switched from third shift to second, then forced to go to 12-hr shifts and shoved back on the 7pm-7am shift,lost my job within a couple months of getting back together with my wife, etc. etc. etc..... so you see, that's a lot of real-life stuff that can interfere with time online!
So, that's my own take on why people disappear...and yes it would be nice if they were able to tell you what is going on, but sometimes things come up quick and hit you by surprise (like my last separation did!), and there really isn't a lot of time to do so. All anyone can do is just wait, be patient. etc.
I lost track of a couple people, and am not sure if they are even still alive as the one had heart problems.... and in that case, all you can do is pray for them, and hope you seem them online again some time.