Velociraptor = ∫ Acceleraptor ⨉ Timeraptor

When I was 10 years old my father told me the grain joke. Do you know it? This extra-terrestrial reports on her travels through space. She has studied the earth. ‘‘An interesting planet’’, she says, ‘‘it is inhabited by grasses of various sizes. Some live in shallow water and others on dry land. They all have two legged creatures working for them. These creatures eliminate other plants so that the grasses may grow without being disturbed too much. They also keep hungry beasts away. At the end of a season, the creatures carefully assemble the grains of the grasses, so as to sow them again on the next possible occasion and set a new cycle in motion. The creatures keep a few grains for themselves to feed on, but overall they expand the grasses’ living space a bit more every year. It is very impressive’’.

Mol, Annemarie. 2008. I Eat an Apple. On Theorizing Subjectivities. Subjectivity 22 (1): 28–37. doi:10.1057/sub.2008.2

I don’t know of such an alternative. A quick solution would be to use something like GeoNotes to take geolocated notes.

As far as a self-hosted solution goes, I’d just like to point out that you wouldn’t need a self-hosted database of places. You could query Ouverture (or Google, OSM, etc.) for places near you, and you’d just need to store the check-in on your server with a basic API. This is an interesting problem, and not super hard to implement.