Does anyone have any experience or stories to share about recovering or seizing usernames or domain names for brands or marks that you own?

I suspect in the very near future I'll be taking this up with twitter and facebook to get the account names/ids that are using my trademarks terminated and assigned over to me.

I should probably have just signed up for these services "back in the day" but I didn't. I'm still not a fan of those services personally, but I can't deny that others are, so I have to move to help my business cater to its audience.