I think the coolest feature of it was its massive database of RSS feeds. I liked being able to flip through tons of categories and add them. However, it wasn't enough to keep me coming back, and that's probably why Google is discontinuing it.
I wish there was some way to export all those feeds, though.
What surprises me most is that Microsoft, which has a severe case of Google envy hasn't created a web based RSS service of it's own. They should make an offer to buy Reader and Feedburner too, since Google seems to have little interest in supporting these products.
That pretty much describes my relationship with Twitter, and almost none of my friends use Twitter. But I don't think Twitter is any less important for that; likewise, don't let your lack of interest in Reader blind you to the fact that it has high utility for others.