Originally posted by xAlienWare
All that site shows is how many PS3s and PSPs that you have activated on your account but it does not let you deactivate them from that site......
As of this moment, the only way to deactivate your accounts from a console is through the "Accounts Management" tab in the XMB of that specific console or by calling Sony's Customer Support.
If you don't believe me then go ahead and try clicking on the "deactivate" button and see if it deactivates it for you.