Doc wrote about Vendor Management Systems to counter Customer Management Sytems.
One technique I picked up from Stuart is to register a domain (preferably your own name), and forward any email to it to your inbox. Then, when you need to give a vendor an email address, give them their name at yours, eg email@example.com. That way, if the subsequently get spam, or unexpected mail, you know who it was. This can confuse people on the phone though - "what's your email?" "firstname.lastname@example.org" "Don't you mean email@example.com ?" "Nope".
Dave wants a way to keep his movie reviews where he controls his own data. We have a way to do this with hReview - post the reviews on your blog, then get the vendors to read them. The smarter review sites, like Yahoo Tech are already doing this.