@sh4SQc ("ssssh Foursquare checkins") is a Twitter Shush Account designed to help minimise the noise created by Foursquare checkins.

If you are a Foursquare user and have set up your Foursquare account to broadcast to Twitter when you checkin then you CAN prefix such checkin shouts with @sh4SQc to help hide such updates from your regular followers (who might not be interested).

If such followers have decided they DO want to hear about Foursquare checkins, then they can always follow the sh4SQc account to tune in to such broadcasts.

...easy as that :)

Obviously it's important that folks know about these shush accounts - one way it to highlight on your Twitter background or your bio which shush accounts you actively use.