Stony Silence stops ALL activated abilities of artifacts, including mana abilities. This is in contrast to Pithing Needle, which has an explicit exception for mana abilites.
To finish out this week's Modern flair, let's talk about a deck called Robots (or back in my crotchety days, "Affinity"). It uses lots of artifacts to make your opponent and his life total very sad. The Legacy version (and the original Standard version) made delightful use of the artifact lands like and pulling double duty thanks to Affinity for Artifacts. While those particular little nasties aren't legal in Modern, they are in other formats where s pretty worthless since they can no longer tap