It does not seem like it would be a plausible model. If it was not SaaS and you were just charging "to get more" of something, than it could work.<p>I will just use one of my websites as an example: <a href="https://mypost.io/" rel="nofollow">https://mypost.io/</a> does not require a login, email, or account to use it. All you need to do is enter in a headline and a password.<p>For a SaaS, you would need to at least require the user to have some type of "account" in which you could identify them.<p>There are "alternative" things you can do, but I think you would still need that "prospect" of an account.<p>An alternative method is to obtain an email address, which is used to know this user is trying to log in. Upon login, the user would be stopped because they technically haven't identified themselves yet. Your app would send a link to the email address, which the user would then click and be able to login. The unique link makes up for the password. So no password is required.<p>Another way you could do it is by offering the user a way to sign by entering a pin unique to them, but again: you would want to require some email address so in case they forget, you could send them the details.<p>Another way in which I'm also experimenting is to just get their phone number as a username. Upon entering it, they are sent a text message, to which they must reply with whatever alphanumeric ID combination is in the text and compare it to the ID you sent.<p>A new way I am also doing things is.. I actually looked at what Hacker News does. You need a username and a password to register, but no email. However, if you ever lose your password, how do they know where to send it? By asking you for your email in the profile, but I don't think they really care if you don't care.. if there is no email to send it to, your sol.<p>What I used to do: Require a username, password, and email address. Why 3 fields? I eventually narrowed it down to just the username and password, so the user could immediately login, but upon landing on the Settings page, an email address would required in order to continue.<p>These are just some clever ways of doing things that you could possibly use, but as far as having random people come and use the web app without any affiliation at all would make it hard to track them down without some sort of identifier and commitment.