You need an email account in order to join a mailing list, so get one of those. Your ISP probably gives you one, but you can also use one of the more obscure email providers like yahoo or gmail if you want. I'm a fan of fastmail on my own domain.
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I understand where you coming from, but I don't think this "modern web-user" is unfamiliar with what email is, so the sarcastic tone is a bit over the top and usually not appreciated on HN.
Instead you could have spent time explaining a better way of browsing the content, or what to consider when reading. Instead of assuming this person doesn't know what a email address is.
Once you have an email address, this content is now available to you! Most mailing lists are free and easy to subscribe to.