Shareaholic is a service for sharing content to different social networks and services. I only use its extension for Firefox from here. This provides me ability to share the current URL to other services, just like I can do in Android.
It adds a button to the addressbar. Click it to view your services you can share to and to customize its Options.
I recommend going through its Options and enabling only the services you need.
I use Shareaholic to share the URL of a webpage I'm viewing using Gmail or Twitter to other friends.
Tried with: Shareaholic 126.96.36.199, Firefox 41 and Ubuntu 14.04