NDA for private alpha/beta users?

There was one company, Ripplin (basically a big MLM scheme) that did this, as a "look how special this is". If you then invited a couple of other people (without being able to say what it is) you got to the next stage. They did make it though, so that the NDA was to see a youtube video, which was a public video, so could easily be found on YT, it'd just make the average user feel like they'd been invited into something special. It worked, and they're doing well. YMMV though, what works for a scammy bizopp may not work for you.

No. As a user I would never sign an NDA.

You want virality and promotions, not secrecy.

thanks guys! This is pretty much the way I was feeling about it.

First, no. Like the other response said, you want an open atmosphere for buzz. It's not very inviting, inspiring, or fun to sign such agreements; it can spoil the atmosphere around your product.

The only way I could see this being justified, is if the product is for government (in which secrecy can be important), or big enterprise (in which you're going to have a few clients to start, and you're competing with some massive companies and don't want to tip them off any sooner than absolutely necessary; signing an NDA still won't go over well, many will refuse). If this is in the consumer Web / app space, or small business space, absolutely never seek an NDA.

If you want to keep it secret, and the product is very alpha, test it with the smallest circle possible, ask people nicely to keep it under wraps; you can even lock the access down tightly, but have no illusions about people sharing what they see or talking about it. As the product gets closer to launch, open it to an ever wider audience.

Second, it'll be almost impossible to enforce. NDAs are a big pain to enforce under the best of circumstances.