I'm considering purchasing an unmanaged VPS with a Ubuntu 12.04 server to host smaller sites that aren't very important yet. My plan would be to install webadmin and basically administrate the hosting end that way. My question is: What am I getting myself into? I'm fairly comfortable with Ubuntu. I know enough to 'sudo apt-get update && sudo apt-get upgrade.'What else would I have to worry about aside from the usual keeping my scripts (mainly WordPress) up to date? 
Unmanaged Ubuntu Server - What would I be getting myself into?
vps;ubuntu
What else would I have to worry aboutEverything short of pretty much the data center being on fire. That's the unmanaged part:  OS/software update? You need to install it.Bad performance? They installed Ubuntu; that doesn't mean they did any optimizing at all.Apache/MySQL/etc. crashed and your site's unreachable? You need to restart it.Security problem? You figure it out and fix it.Data center burned down? They'll probably replace the server, but you better have your own backups of the data.In reality, you need to read the host's terms for a final answer on this, but generally speaking, it's going to be as above. They give you a server with maybe completely default installations of a few things like Apache, but then you manage it from there.