What are some alternatives?
When comparing Heya and dropdrop, you can also consider the following products
World Brush - AR app where you paint on the real world for others to find
Taylor - Your personal travel assistant that tells you where to go
TapTag - Leave photos for other people to find
Pana - On-demand travel concierge
Run an Empire - Turn runs into adventures
SPAYCE - Leave memories everywhere (iOS)