How can I stop Nathan/Zak from emulating me with a copy of my profile name ?

All you can do is report, report, report, and report more. Did I already mention report?

Sad truth is there's really nothing that can be done about this.

Do you know how many OTHER people named Zak or Nathan actually use Y!A? What are Y!A staff going to do? Delete every account that has your same name? They aren't going to do that, buddy. You can report a you want. Nothings going to get done. Y!A are just going to throw your 'problem' in the lost cause pile.

Just let it. Make a new account under a different name and start something new. Don't even let people know its you because that's going to open up another window for Zak or Nathan to troll you more.

You're welcome for this free advice.

Ask questions, praising Christianity and Judaism, in his name. He will have an apoplectic fit.

? is hardly a unique name. At times we've all been stuck with that. I think you would have a hard time convincing Yahoo that it was cloning.

We are all sick of him and his alter ego Carla. Don't take the bait and ignore him he's attention seeking.

Yeah OK Zac

I think we all know nathan whatever or whoever the voices tell him to be. So I wouldn't worry to much about it.