Twitter’s biggest problem is that it doesn’t make it easy for non-tech people to adopt this technology. If they want to gain critical mass, it needs to be more viscerally navigable, otherwise people will stick to the technologies they know: text messaging, blogging, email, Facebook/MySpace, or IM.
The founders had an intention to get people to quickly and precisely tell everyone what they are doing in less than 140 characters, just like a text message. In principle, I think the idea makes sense as a supplement to an established offline relationship. However, by not allowing users to elaborate on thoughts or ideas within Twitter, one ends up saying nothing meaningful at all. Although Twitter has immense possibility to facilitate flashmobs and culture jams, I have yet to see how Twitter is better than IM, email, or texting.
On a side not, I recently did a little experiment with Twitter to see if it could drive traffic to my blog by generating a series of phrases I posted into the public timeline of Twitter. I posted a new phrase every one or two hours for 24 hours. Long story short, my blog has not documented any traffic directed from Twitter. So sad!