1. Buying friends. CNN announced Friday that it had acquired @CNNBrk, a Twitter feed that serves up links to CNN breaking news stories. Now that people are rewarded for selling followers, an entire underground economy will probably emerge. Perps will use dirty tricks to build a large number of followers, then sell those accounts to big corporations. The end result will be a large number of accounts that suddenly turn into sources of Twitter spam, and a large number of users who feel they've been tricked.

2. Username squatting. When I started following @CNNBrk, I thought I was following CNN itself. I didn't learn until yesterday that it was just some dude who grabbed the CNNBrk name, copied the CNN logo and served up links to CNN content. CNN's acquisition of @CNNBrk showed everyone that username squatting on Twitter pays. Expect to see millions of people signing up using trademarked IP, hoping to cash in later.

3. Forgetting to grow a business model. The trouble with not making money is that Twitter won't be able to keep up with demand. Which means more fail whales, slowdowns and problems. (The fail whale is a picture that's displayed on Twitter when the system breaks, usually because of excess activity.)

4. Invasive advertising. Ads on Twitter would be OK. Paying to not see ads would be OK, too. But ads that cover the screen or otherwise delay posts could harm Twitter badly. Twitter is about speed and brevity. Big ads that are fine elsewhere won't work on Twitter.

5. Spam. The good news about Twitter is that everything is instantly searchable. The bad news is that everything is instantly searchable. Stories abound about a user whining about some product only to receive a quick e-mail from the company they complained about. Want to compare network applications products? Visit the IT Product Guides now.

Companies are using Twitter's great search tools to find out in real time what people are saying about them. This could all be further automated. I'd hate to see an entire ecosystem forming around the triggering of spam to your e-mail in-box every time you tweet something. This spam could also be used as a form of "punishment" that stifles criticism. Another form of spam is unwanted ads sent as direct messages. Once this is automated, our direct-message in-boxes could be filling up with garbage. Spam ruined e-mail, and it could ruin Twitter.

6. Bugs and viruses. Twitter allows links, and links could send you to the same kind of sites and trigger the same kinds of downloads that initiate the downloading of Trojan horses onto your system. Twitter needs to stay on top of this before it becomes an industry.

5 things that wont!

1. Celebrity culture. Sure, Oprah and Ashton now dominate the Twittersphere. But to say celebrity tweets, celebrity gossip and celebrity trash-talk will ruin Twitter is to not understand the very nature of the service. Twitter is the one form of communication where you can individually choose who you listen to. This is different from, say, comments on Digg or even articles in the newspaper, where you have to wade through muck to find gold. Sure, we'll be hearing more than we want to hear about celebrities on Twitter. But we'll be hearing about it on TV, in blogs, and in magazines and newspapers. Those are the things that will be ruined by celebrity twittering. But on Twitter itself, we can just turn that stuff off.

2. Media hype. Twitter is overexposed in the media. But that just wrecks media, not Twitter. There is no such thing as unwanted communication on Twitter. If you chose to follow someone, by definition you want what they tweet.

3. Marketing and PR. Again, missing the point. Twitter will be great for people who want to get marketing information and interact with PR people (I'm one of them. I'd much prefer to tweet with PR people than exchange e-mail). But for those who don't, they can just stop following. And because of that, Twitter rewards marketers who communicate in a straightforward and appealing way and punishes anyone who uses some kind of exploitation. The marketing industry and Twitter will improve each other.

4. Big business. As Twitter's usage grows, of course, companies are going to build massive followings by doing things like raffling off expensive goods to followers. But this won't affect your own personal tweets any more than McDonald's ads affect how you make dinner. Corporations will be over there doing their thing, and you'll be over here doing yours. It only affects you if you choose to participate. Want to compare network applications products? Visit the IT Product Guides now.

5. Google. OK, Google could ruin Twitter. But I don't think it will (if it acquires Twitter). Google would most likely grow the service even more rapidly, and keep its functionality pretty much the way it is, as they have done with other acquisitions. Plus, there are many ways Google could improve Twitter, including integrating it into Profiles, Chat and Gmail.

So if you're a Twitter user, enjoy its many great qualities while they last, because they may not. However, if the geniuses running Twitter remain faithful to the original vision (as other companies like, say, Craigslist, have done), then Twitter might stay great and become even greater.