The Firefox 2.0 browser already comes with Google as its default search, but this advertisement implies there are more default Google services integrated into Firefox. Is it just Google Toolbar, or does it include other things?
You can choose Google Reader as your default Feed Reader in Firefox. On my Linux box, I would go to Edit->Preferences->Feeds, and choose Google Reader in the listbox titled "Subscribe to the feed using:". Now everytime an orange icon comes up in Locator box to the right, it will take you to Google Reader where you can subscribe to that feed.
Be warned though, this makes it so easy to subscribe to feeds, you might subscribe to too many, and then end up doing this. :)