alanback:

And there's very possibly a correlation in that idea.

Pythagorus: As BBW said: "They can continue to write and think they are writing to you, but you will no longer have to read it.". I tested this by blocking a friend in a game just now. All the messages - his and mine - disappeared and then reappeared when I unblocked him. Presumably, then, the offending diatribe plus any additionas will be in the game record for such time as the writer is unblocked.