For the past 3 years I’ve kept track of every song I’ve listened to intentionally using social music site Last.fm.  It has lead to some amazing recommendations and it’s easier now than ever.  Here’s how you can do it too:

1. At home

Download the Last.fm software and install the plugins for Windows Media Player, Winamp, iTunes, etc.  As you listen to music on your computer it scrobbles (uploads) your tracks.  If you have a home theater PC and use XBMC or Boxee they both have built-in support.

2. At work

Most of us aren’t able to store a bunch of mp3s or install software on our office computer.  Fortunately there are several streaming options:

- Last.fm’s site. You can listen to stations built around music you’ve listened to, an artist, a genre, etc.  There are more options if you pay for them.

- Lala.com.  Recently aquired by Apple, Lala lets you mirror your digital music collection in the cloud and stream it from anywhere.  Scrobbling is still a beta feature so you have to request it by going to My Lala -> Settings -> Beta.

- Last Pandora.  Scrobble songs from Pandora internet radio.  This is the best of both worlds and super easy to use.

- Rhobbler.  A tool that scrobbles your Rhapsody tracks.  I don’t use this but it looks as simple as Last Pandora.

- The Hype Machine.  You can enable scrobbling in your settings.

3. On the go

If you regularly sync your iPod with iTunes, just install the Last.fm software and it will automatically detect it and give you the option to scrobble your tracks.  There are also official Last.fm apps for the iPhone and Google Android but they only allow you to stream.  If you want to scrobble the music you have stored on your phone you will either need MobileScrobbler for the iPhone or Scrobbledroid for Android.