Translated, it pretty much means the following: US companies have PR and media experts who told their CEOs "You thought that blogging was stupid, and look where it's at now. You don't want to miss the Twitter train, because Twitter is the next blog." European companies either don't have these people, or they simply don't care.
Loic Le Meur, founder of Seesmic, told Forbes that "if European CEOs think it is a waste of time to Tweet, it is arrogant and a wrong step in their company's strategy. Twitter is an efficient way to get closer to your clients."
I, however, as much as I love Twitter, am not convinced. A company blog (or a frequently updated website), especially if it's a web-based company, is an absolute must. I hate it when a web startup doesn't have a blog where I can check what they're doing and what they plan to do next.
But Twitter is much more personal. I don't follow "corporate" Twitter accounts much, because information about a company randomly spewed in tiny 140-char chunks are pretty much useless to me. If the CEO really wants to tweet, great; but if it's a fake, corporate thing where he/she simply has an assistant writing the tweets, it's pointless, because people will get it, eventually.
Ultimately, it's just a question of audience size; if Twitter gets big enough in Europe, then yes, all the companies will hurry to create an account (or dozen), fake or not. If it doesn't, and they don't, well, I'm not going to shed any tears over it.