So right now I’m logged in both Primal and Nostur, primal has my walletofsatoshi setup. And on Nostur I don’t see the walletofsatoshi in my account. Does that mean that people who use Nostur can not zap me? Only people who use Primal? 

 It’s a protocol rather than a platform. If you have your wallet address entered into any client in Settings other users will be able to zap you. If you just keep experimenting, within a couple of days you will have it all figured out. 

 What if I’m on a platform and another user is on a different platform, they won’t be able to zap me? 

 They can. As long as your wallet is configured into your client.