‘Regret is basically a sorrow over a past alternative which was available to us, but which we missed’ (Aaron Ben-Ze’ev, The Subtlety of Emotions, p. 493). (See the entire section which begins on this page.)
So basically Craiglist is encouraging us to prevent future sorrow by using its services. Clever.
However, we may also regret not missing some of these connections.
Not so clever.