Shabam wrote:

> My question is regarding performance, not if it's doable.

I should expect it to be the least of your problems as far as
performance is concerned. Just use a mass-vhosting configuration.

> Also, the mod
> you've recommended doesn't fit well because it allows too much control for
> end users to abuse it.

Quite the reverse. Firstly, as with any other module, users get exactly
as much control through .htaccess as the system administrator permits
(and a sysop who is concerned about performance will of course disable
..htaccess altogether). Secondly, because it works by parsing markup,
it won't get subverted by the kind of tricks that users of services
like geocities traditionally use, which puts them in a perpetual arms
race with their hosts.

Anyway, your decision. And I'm sure there's a growing market out there
- if you can reach it - for a free service that won't automatically
invalidate its users pages as these auto-ad-banners traditionally do.

--
Nick Kew