Font Awesome icons -
fortawesome.github.io/Font-Awesome/icons/
this is very popular icons for websites, this icons use every new RocketTheme template and this is good for economy load of page, because this is no images like .png or jpg, - this is fonts with icons (no typical images)
this is be good, if i can use for Social networks buttons - this icons from Font Awesome, especially if i use template from RocketTheme or my own template with this icons.