Have you been bombarded with spammers on Live Messenger telling you to check out some Look9683 spammer site? The good news is that you can completely block them, but sadly they won't actually feel physical pain. If you aren't sure what we're talking about... then you probably aren't using Messenger: The first time you receive a spammer message like this, you will be prompted with an option to block messages from unknown senders, which is exactly what you want to do. The problem is that if you don't choose this option the first time, you won't get the same option again.

  Normally if you choose block, you'll be notified that this blocks everybody who is not on your allow list. As far as I'm concerned, that's just the way I like it.

If you've mistakenly or purposely chosen to allow on the earlier screen, you can still block all unknown users—you'll just need to take a trip to the Options panel. Here you'll want to check the box for "Only people on my Allow List can see my status and send me messages". Then you can setup your Allow list if you want, or block other people.

If you are using Pidgin to access your Windows Live / MSN Messenger / Hotmail / Whatever MS re-named it as today account, you can go to Tools \ Privacy:

Then choose the account in the "Set privacy for" drop-down, and choose "Allow only the users on my buddy list" in the lower drop-down.

This will stop those ridiculous spammers directly in their tracks.