I've used Bloglines for a few years now to keep track of some things I like to read: some personal blogs, a few library sites, a site with a tip about dogs every week, a few sites with photographs.
But I have to say, for all I find the newsreader useful, I don't really like it. I can't say why, exactly.
On my personal blog, I keep a long list of links. I find it's more my style to think "I wonder if Karen has posted something new" while writing in my own blog than to check the newsreader. It's sort of the way I read in general, more random than organized, more serendipitous than planned.
Yet I keep using Bloglines for one primary reason. It alerts me to sites that I thought were more or less dormant when they spring back to life.
And that's worth a lot.