Slashdot did this - and possibly still does, no idea since I left that site aeons ago - although the limit was lower than 140 characters. It led to people addin

Slashdot did this - and possibly still does, no idea since I left that site aeons ago - although the limit was lower than 140 characters. It led to people adding random nonsense to their comments to keep the comment filter satisfied. Since everyone knew there was such a content filter and the added guff was marked as such it did not lead to those comments being down-moderated, i.e. all it did was clutter up the site.