Domain names are really cheap, in marketing terms. This morning I registered a “dot co dot uk” for two years for less than ten pounds, and I’m sure there are even cheaper places if you shop around. It was for a domain name I don’t need at the moment, but I expect to find a good use for it quite soon. The main reason to get it, however, was to ensure nobody else did.
Have you got domain names registered for all of your main product lines? You should. If you’re thinking “but it’s a pretty obscure name and product, we’ll register it if we ever need it, nobody else will be interested in it”, you’re taking a gamble. Read Why, Oh Why Didn’t I Buy That Domain Name? on E-Marketing Performance for a tale of woe.