Just started using Google Reader this week, and I'm a bit mixed on it. From a technology & efficiency standpoint, it is great. You simply tell it which blogs you read a lot and, on one page, it compiles all new posts. This way you need not visit 10 different pages at various points during the day to see if there's anything new, you just need to go to one page. Nice and simple, with few glitches (if a blogger is prone to putting a lot of stuff below the fold -- Krugman does this a lot -- then you'll likely need to click from within Google Reader to visit the actual blog).
But what worries me is that the authors don't get a 'hit' to indicate that you visited their site, and obviously you didn't see any of their advertising. So instead of The Atlantic or The New York Times or whoever getting ad revenue from their banners, you instead just stay within Google (of course, Google controls a lot of the ad revenue anyway, but you see my point). Oddly, the Google Reader page itself doesn't have any ads on it, though surely that will change.