I've created a Chrome extension for myself that I wanted to share for those of us using the Spotify Web Player. I made it for fun, and have no commercial motivation behind this, but felt others could find it useful as well.
Essentially, it allows you to view playback information (artist, track, etc.) from a popup button, as well as control playback from any tab, and any Chrome window. This is really useful if you constantly find yourself with tons of tabs and windows open.
It allows you to also set keyboard shortcuts for every action, like play/pause, next, previous, and more.
It also support numerous other online sources, such as Pandora, Google Music, Grooveshark, etc. You can find the whole list on the extension page.
On top of that it will scrobble from every source it supports, if you are a last.fm user.
Let me know what you think!