I'm trying to block someone on my list, but this contact is a lot more IT-savvy than I am, and I really know peanuts about computers. I'm a bit paranoid here, so please bear with me.
I'm using Windows Live! Messenger version 8, with Plus! installed.
If I block someone on my list, is it for certain this wall is impenetrable, that there are no existing plugins or hacks for someone I've blocked to see me online or even detect that I have signed in to the network (even though perhaps I still appear offline on the contact's list)?