Everyone uses Twitter in different ways. Some people seem to use it like e-mail, or even instant messaging. They are forever sending little messages back and forth to each other. When you look at their sites it's hard to find out what they're really about - unless you scroll down quite a way and find an actual observation, suggestion, or opinion that makes sense in its own right.
It can be like watching a conversation across a room at a party. You hear snippets of it, and think you might want to contribute, but feel that doing so might be a little rude. You feel a little excluded, and decide there would be no point in doing so.
I think a better way to use Twitter is to really apply the definition microblogging. That is, you should eschew the social aspects of it a bit, and instead try to make each tweet pithy, informative and self contained in itself.
Of course, you should include a link to another blog post, site or article. But it's advisable to jam as much information and insight into those 140 characters as you can.
Two things happen. Firstly, people will be in no doubt about what you are about and you'll get followers whose interests and opinions are more like yours. They're also a bit more likely to retweet your tweets.
After a while you'll also amass quite a lot of good, concentrated and unique keyword rich content. That's great raw material for articles and longer blog posts. (Also, I'd imagine it's also a lot better for your Twitter site's SEO. If you are just linking to articles and automatically importing their headlines, or just retweeting others' tweets, then your site will have a lot of the dreaded dupe content.)