This kind of advice pops up on HN from time to time and while I believe it to be valuable, I guess it is at least incomplete. Here are two stories from my failed ventures to augment this advice: 1) Years ago I started a small side-business with a few colleagues. It was a web-based service for a very specific group of clients. Best of all: The idea had already been validated. We had our first paying customer before we…
It's counterintuitive to some extent, but consider a two-phase signup process: a landing page plus an email validation of some kind, or perhaps a two-step signup process on the landing page. There will be a noticeable drop-off between Step 1 and Step 2, and that's good. Those are probably people who would have washed out anyway, and you no longer have to waste time catering to them as false positives. [1]
I'm not saying this was necessarily your issue, but a lot of people run into problems with hypothesis testing by conflating it with marketing or growth hacking. It's not. You're not trying to optimize a hypothesis test for pure signup volume. You're trying to use a hypothesis test as a filter: for the right audience, for your problem/solution statement, and for the value proposition you've chosen to test.
You don't want signup to be a total pain in the ass, but at the same time, you don't want it to be so easy that it loses meaning as a signal of intent.
[1] Caveat being that you still want to probe, and perhaps ask people who've bounced between 1 and 2 why they did so. Sometimes it really is just a UX issue. But in my experience, if someone really has the problem you're addressing, he or she will stick through a two-step signup or validation process.