If you find that you constantly share links with friends through Twitter, Facebook, email, etc. then this add-on is for you. There are literally dozens of services in Shareaholic that can be turned on or off so you can set up only the ones that you use. Chances are that just the act of going through the setup will introduce you to some services that you didn’t even know about before.
The ones I have set up, for example, are Facebook, Twitter, bit.ly, Google Mail, Google Reader, LinkedIn, and Microsoft Outlook. Sharing the current page or a link on the current page using any of these methods is just a click away.