We shortened it because of the linkbait "you", or rather the even-more-linkbait "you don't". Take that out and you get "Venmo Scammers Know Something", which is redundant. Take out the redundancy and you get "Venmo Scammers".

Suggestions for a better title are welcome, as always, but don't forget that HN's rule is to use the original title unless it is misleading or linkbait.(https://news.ycombinator.com/newsguidelines.html)

Their original title was "It's Shockingly Easy to Get Scammed on Venmo" (it still pops up on google like that) but it seems they've decided 'shockingly' alone is not baity enough. But it's a decent title without it. The article is not so much about Venmo scammers but about how easy it is to get scammed on Venmo and how Venmo isn't going to help you.

Ok. That doesn't show up as a title to me, but it is a heading on the page, so we'll use it. Without the "shockingly", obviously.

Oh they just changed it, for whatever shocking reason. But Google (and, shockingly, every content-farm around) remember.

http://i.imgur.com/OdLJRIy.png