Hosting multiple sites with one IP address

[Head Boy]

I've got several hundred domains spread over a whole range of hosting companies. You just open virtual account with them and load the domains. Hosts like www.varzi.net will give you a control panel and you can just add the domains yourself. Other hosts such as www.cyberwurx.com require you to submit a ticket to add a domain, but as they usually respond in about 5 minutes, it isn't a problem.

One disadvantage of using a single IP is the the search engines will lump all your domains together, and they may not count your interlinking for SE promotion.