you'll need a dedi server ..then you can easily set any limits you need to impose on your customers ..

ok, but what about the mailing list feature. how could I provide one for each user that gets a site with a subdomain? I suppose this feature could just be a simple list that builds a link that when clicked would load THEIR email program and puts the list of names in the to field.

Normally email is on a per-domain basis, correct? Is it possible to give each subdomain the ability to send email from their account via the server?

I think I might look into setting up my own server and hosting it myself.

You definetely need a dedicated server if you are planning to offer 1GB of space to each user. You might even need a few servers, or more like a 100 if the site grows.

>>I think I might look into setting up my own server and hosting it myself.

Are you talking about colocation? I recently did the math on this concept - it's probably best to buy a dedicated. Here's what I did to figure this out, you tell me if you get the same result.

Go to any host and look at their colocation fees and what it includes. Most of the time it includes bandwidth, power, cooling all at reliable levels (backups...).

Then go to somewhere like Dell and configure a server. Include in that configuration the services you'll get with dedicated (2 hour on site hardware replacement). Add those services to the Dell configuration and look at the lease payment. Add that to the colocation fees and you'll find it's less expensive to lease a dedicated server from a host.

I am with Moltar
your biz concept is quite scarry :)

Do you forecast some GOOD $ revenues, better be