One of the first things I did when I started using Google Reader was finding the bookmarklet to make subscribing to feeds easier. Unfortunately the first few times I used it I didn’t realise I had to click the “Subscribe” button in the Reader interface. It was hidden away in the top right of the page. I was too busy looking at the feed contents to notice it.

Tom and others have pointed out that Reader added a search feature but this “You are not subscribed yet” warning is a nice usability improvement that I haven’t seen anyone mention yet.