Safari: One change in the Mountain Lion version of Safari is the removal of the RSS subscribe button. Subscribe to Feed is a Safari extension that brings the button back so you can quickly add RSS feeds to your favourite RSS reader.
The RSS subscribe button has been in Safari for a long time, and if you find yourself missing it in Safari 6, Subscribe to Feed is a simple way to get it back. When you click the Subscribe to Feed button on a page with an RSS feed, the extension will load up your favourite RSS reader and add it to your subscriptions. You can't subscribe directly to your Google Reader, but if you use an application like NetNewsWire or Reeder, it'll open right up.