Topos drawn on the rock, by the people who climbed it.
Search walls, crags, regions and problems, and read topos with the line of each problem drawn straight over the photograph. Both reading and contributing are free to everyone, on purpose.
A line on a photograph, not a paragraph
A topo is a photograph of the boulder or wall with a line traced over it for each problem, and each line is tied to a real entry in the problem database rather than floating loose. That is the difference between a picture and a topo.
Free to read and free to add to, deliberately
Topos sat behind the paid tier and the gate came off both sides, viewing and submitting. The reasoning was that the binding constraint is not conversion but content: a catalogue only becomes worth anything once it is full, and the people most able to fill it were exactly the ones locked out.
Moderated, and the photographs have owners
Locations and problems are submitted by climbers and reviewed before they become visible to everyone, with a queue so nothing sits pending and invisible. Rejections come with a reason, sent to whoever submitted it.
Photographs are copyright in a way that route names and grades are not, so uploads carry rights information and there is a reporting and takedown route. That is unglamorous and it is the part most community catalogues get wrong.