It's not just that the scroll is infinite. It's mainly that the things displayed are optimized to keep you "engaged" (codeword for addicted).

Yes, facebook intentionally does everything to get people to spend as long as possible on their website. It's their business model.

I wonder how much the infinite scroll amplifies the effect. Not showing page numbers is reminiscent of casinos eliminating indications of what time it is (i.e. ways to intuit that you've been sitting at a slot machine for 4hrs).

And of course the random choice of things displayed on the infinite scroll - deliberately emulating a slot machine effect.

The comment box is where addiction happens for me. Once I stay logged out and browse the pull is just not there anymore.

I've been on this site for maybe 6 years and only just recently created an account. If I see the same problem this one will go too.

HN actually has an anti addiction feature, namely noprocrast, in the account settings.