A popular method used by hackers is to sign up for a virtual server with a stolen credit card. If they are careful and only access it through a proxy, their hacking attempts are virtually untraceable. With the amount of hacking going on lately by Lulzsec and other groups, there is bound to be a lot of collateral damage.
Sounds like a very black hat way of taking out your unprepared competition. I'm sure you can buy this sort of service somewhere - get a hit on a datacentre/rack by security services in response to highly illegal activity perpetrated in the open in order to cause the most possible disruption.
I didn't mean to imply they would intentionally do that to take out competition, although that is indeed a possibility. The main purpose of having a stolen virtual server would be to launch attacks from.
The truth is even if you rented a virtual server in the same data center, your chances of being in the same rack of hardware are pretty slim.
