In footers everywhere I'm seeing those lines that say "Made with love in San Francisco" or "Coded with (heart symbol) in New York", or some other variation. They seem to be really popular. My question is -- why? How did this trend come about, what purpose does it serve UX-wise, and should it be part of the UX on my site?
(Here's an example, somebody even made a NPM package for this: http://jugoncalv.es/heart/)