If you think Twitter is a waste of time (and not the most wonderful thing since Facebook status updates) and as a result don't have a Twitter account, I still have one piece of advice if you're a business (or have a trademark).
Stop what you're doing right now and go create a free Twitter account. When you do so, make your Twitter account name your primary brand name.
This is free, takes only 30 seconds, and you may be thankful someday you did. If not, no big deal, you wasted 30 seconds.
Why? Because there's nothing stopping someone from grabbing your company name (even if you have it trademarked), and it's near impossible right now to do anything about it if they do. Sure, you have the legal rights to your company name, if it's trademarked, but if I were you, I'd rather just grab it for free in 30 seconds in case you change your mind in a few months and decide Twitter is important to you after all.