My minecraft server lasted about a year and the thread had about 300 posts, 15 pages or so of replies. It was mildly popular, but the problem was it was hard to keep users for long. We had about 4 regulars that stuck through the server throughout the entire time it was open, which included me as the owner (and excluded my two co-owner ops, which should give you an idea of what I'm talking about). Then we had about 20 users total who came and went, and the most we had online was about 20-25, which lasted for a couple weeks to a few months. Then it died down, I shut down for a while, brought it back up, and again the activity peaked at about 15-20 online during the day, and after a few weeks to a few months, died down again.
Then the activity tapered off. The reason for that was partially my fault though, I refused to ban trolling users, and users who used hacking clients. Nothing they did was malicious, all they did was fly and cheat a bit when pvp'ing (which I would ban them for a day or so for) but I left them unbanned because they were part of the core 5 users who were actually loyal throughout. Additionally, there was periodic downtime due to my terrible host. Lastly, though I stopped spawning things about halfway through the lifespan of SytheCraft, my other admins would continue to cheat while they played, which would ruin the game. The game ceased to be fun when people cheated. People's houses got demolished, factions were destroyed easily, and no one went anywhere while one faction would sit and absorb everyone's hard work because they got an early legup with spawned materials. These sorts of situations led to the necessity of the server being reset, and that would lose much activity because the transition was never smooth.
The only reason my recent version of SytheCraft was successful was because the children at the YMCA I worked at got addicted to minecraft, and they wanted to play on my server because they looked up to me and thought it'd be really fucking cool to play on something I made. So that added about 10-15 active users, though they were all immature and young and didn't know how to play well, so that added an sense of mediocrity to the server that my sythe/internet users disliked.
So, to answer your question, the interest in a MC server is minimal. Unless I was doing something drastically wrong, you may only end up with 10-20 active people for a while, and it'll die down to 4-5 as the weeks go on. People tend to get tired of minecraft, and there aren't enough minecraft-savvy users to keep refreshing the interest.
I don't know if I'd participate in the server personally, I'm still bored of minecraft. Additionally, I dislike being a regular user on servers, the only way I like to play multiplayer is if I have 100% access, if not to the server, at least to the plugin functions, even though I try my hardest to play 99% legit without admin advantage. I'm just a control-freak like that
