Spamming/Advertising - You cannot post advertisements of any sort in any forum. This includes products, services, or web sites from which you'd directly or indirectly benefit in any way.
EXCEPTIONS (may be objected to, at the discretion of the moderators)
#1: Unaffiliated Announcements - If you see a great deal somewhere, you're welcome to share it with everyone by posting it in the "General Opinions and Reviews" forum if and only if you are completely unaffiliated with that deal.
#2: Signatures - When posting a useful response, you may include your own web page (or that of your company) in the signature of your message. However, this does not precede other rules. (That is to say that you can't mis-use HTML in your link, provide links to naughty web sites, etc.)