Firefox and built in RSS feed utility
Don't know how many people have downloaded and installed the newest release from Firefox (1.0) but they have a built in RSS feed. If there is a RSS feed available you will see a little icon on the bottom right of the browser. (such as when you are on the AO main page) When you click on it, it says "suscribe to RSS feed" and you can create a bookmark for it. It is a very useful feature to have.
Now the part I don't like about it.
It gives you the option to open RSS feeds in tabs. It will then proceed to open ALL of the RSS links in the different tabs. If enough people started using this all the time, isn't there a potential for it to DOS the servers? I could see if it opened one tab at a time, but it opens all tabs and tries to load all tabs at once.
A site like AO probably wouldn't have a problem with this... but much smaller sites would.