In Drupal 6 & 7, the AddToAny module can be used to provide links to 3rd-party services for sharing content on your site.

This module comes out of the box with some features that may not be wanted by all users.

The following CSS can be used to limit it to particular services:

#a2apage_PTZ { display: none !important; }
#a2apage_EMAIL { display: none !important; }
.a2a_tabs { display: none !important; }
.a2a_menu_find_container { display: none !important; }
.a2a_menu_find { display: none !important; }
.a2a_menu_show_more_less { display: none !important; }
.a2a_menu_powered_by { display: none !important; }
.a2a_i { display: none !important; }
#a2apage_facebook { display: block !important; }
#a2apage_twitter { display: block !important; }
#a2apage_google_plus { display: block !important; }
#a2apage_delicious { display: block !important; }
#a2apage_digg { display: block !important; }

Also, the module adds a third-party tracking pixel, which can be removed by adding the following in the custom JS settings section of the module administration page:

a2a_config.no_3p = 1;