This advice is too generic. There are many, many applications where a persistent identity is required. What would happen if Hacker News had completely anonymous users? :P
A ticketing startup is a good example of a startup which could be used without a dedicated user account. But that's the minority.
He's not talking about requiring accounts for all users, only visitors. You can browse HN without limit without an account. Also, it is trivially easy to make HN accounts. My guess is that the OP approves of HN.
These are just usability guidelines, almost all of which are dealbreakers for me when I visit sites.
For example, when I use my password manager to generate a 64 char password for a new account somewhere, and get an error message saying "Please limit your password to 3 to 20 chars using only letters and numbers," I just have to laugh to myself.
I mean, think about what this tells you about the creators of that site.
I would say that in my experience, account creation at online retailers (even Amazon) is very rarely something I've found useful for myself. It may well benefit the company.
I don't want my card details to be saved, and typing in my address and card number take less than a minute anyway. Newsletters almost universally go to spam because I'm not a landowner who has the disposable income to just buy arbitrary things that are advertised to me.
I think generally developers are aware of this, but they're chasing the few that do respond to such tactics.
The advice isn't "don't have accounts," its "don't make visitors make accounts." Having an option is good... if you don't plan on coming back or you're worried about your security, you don't have to store anything on their servers. If you're a frequent customer and you want the convenience, you can make an account.
But I don't want to hand off my FB, Google, etc to various websites. If a site only offers that, I simply close it and find another part of the web to browse instead.
2. Don't force visitors to use a 3rd-party provider. Always have a local option. As a counter point to (1), many visitors won't want to use their Facebook/Google accounts for authenticating to other sites.
I tend to prefer the oauth options myself... I don't want to have to enter a bunch of information, or add yet another site to lastpass if I can avoid it... Though, if they ask for too much, I tend to just deny and move on...
For example, it's interesting that a site within the past couple of minutes to sign into could use a local account, facebook or google... I clicked fb first, they wanted contact info and my full friends list... google, just my email... so I let it in with my google account.
I think it really depends... I wouldn't offer social logins without also having a local option, but it really depends on your audience.
But it requires you to have an account with some other party, such as Facebook or Google. What if you don't want that? Suddenly this service that you do want to use becomes unusable.
And it also tells Facebook / Google etc what other sites you use, which is none of their business (not that they won't grab that info because of like buttons, analytics, embedded fonts or hosted JS but that's another matter).
Can't have your cake and eat it too. If you complain that you don't want to have to log into sites, it makes less sense to complain when there are ways to have unified logins so that's not necessary anymore.
A ticketing startup is a good example of a startup which could be used without a dedicated user account. But that's the minority.