You could always write on other people's whiteboards. Seeing as how they are put into public spaces, they can be used by the general public, as long as you don't do anything offensive.
i have just put the greatbeyond on my facebook account. For those of u who dont know what facebook is, its a huge network of millions of college students and alumns that is becoming very popular these days and it links u to all ur friends that u contact that have an account as well or ur friends friends and so on. You can check out people from any school u so well desire as long as they r signed up for facebook, which i know UMBC is cuz i have buddies there so get on cuz i know there a quite a few people that go there from this site. Anyways, people can check out all sorts of things about u and u can fin people u have tings in common with and its a good source of info if u r looking for personal stuff and i advertized the site there so whenever anyone looks at my profile they will see the link and want to see the site because i provided the fact that im on it and i would like to think that there r some people with nothing better to do and since i know several people addicted to the facebook im sure its only a matter of time b4 someone new visits!
I tried something similar with Friendster, and then again with Orkut, but they never really seem to go anywhere. After you've signed up all your friends, it serves as a neat tool to see who else signed up, but it doesn't work too well for meeting new people.