Hi, unmetered means non metered, that's to say your host won't control your bw. However unmetered doesn't mean unlimited, remember that with 1mbps you can spend up to ~300GB of bw per month, so 10mbps unmetered has a limit of ~3000GB, 100mbps... 1gbps....
I dunno how to explain it better.
With 1000 people playing you'll need a powerfull server, I'm dunno too much about gaming servers, so I leave this for anyone who wanna answer you.
Remember that you're going to want to gage how much CPU/memory this game takes up per player and rent a server accordingly per the specs. This is probably as, if not more, important than the bandwidth. Now, if all of these people are playing java chess, that's a lot different from say...Counter-Strike or something. What kind of game do you have in mind?
I assume this will be for a MMORPG style game in which case a shared unmetered connection is probably fine. In these style games ping really is not that big of an issue so the instabilities you can come across in a shared unmetered environment are not that evident.
In a mmorpg setup your biggest assets are going to be CPU and RAM, with RAM being the more important of the 2. See if you can get an accurate figure on what each player will take up before investing heavily in hardware. You could find yourself way under or way over what you will need
i find one on theplanet,MatriXtreme Xeon dual 2.4GHz, 2048 MB RAM,2 x 120GB Hard Drive,but i just worry about the shared unmetered connection .Because somebody told me at least i should get a Decedicated 10Mbit server..