alt Hacker NewsAny amount of friction reduces the amount of slop. What proportion of clankers are going to realize that they need to warm up the accounts two weeks in advance? Answer: a proportion that your never going to see with that barrier in place.
With a couple few layers of defense, you'll weed out almost all of the bad actors. Without strong monetary incentives for spamming, you also avoid most persistent actors.
With enough layers you will also weed out almost all of the good actors. Normal people are busy and don't have time nor patience to jump over too many hoops to promote their cool new research, or to respond in a thread where someone linked it.