Quote from the staff announcement:
We've created a new way to scrobble with Spotify. Instead of configuring each application or device separately, you now only need to link Spotify to Last.fm in your applications settings page. Once connected you'll be able to scrobble wherever you use Spotify. This brings back scrobbling to Spotify's web player, and opens up the ability to scrobble from Spotify Connect devices like games consoles, TVs, Amazon Echo, etc.
This new feature is in beta, and there are some known issues, so please read the following before connecting..."
Read more in the original announcement.