It appears that tapping on the hearts and collecting the sparkles are connected to usage of the Wall.
I've noticed the newsfeed alerts me to a visitor, but the sparkles haven't appeared, but if I write on my wall, or their wall, the sparkles appear.
I think because the Wall isn't as easily accessed and not used as much in this game, a lot of farms aren't noticing they have sparkles and aren't clearing them.
The heart social levels don't seem to be as high in this game as other TL games, maybe people couldn't be bothered, as hearts aren't always available and clearing isn't done as often, making the profits from socializing decreased.
We shouldn't have to be active on our walls, to make tipping/helping beneficial, players who choose not to use the wall should still be able to see the sparkles quickly and readily.