#Geospatial software devs: Please don't forget to add an attribution to #OpenStreetMap contributors to the footnote of maps you add to your pages. OSM is a voluntary project and the least you should do is give contributors the credit they deserve.
The main geospatial libraries for webmapping, like OpenLayers and Leaflet, have an "attribution" key when you create a "layer" or "source" object. Please make use of it when using tiles from OpenStreetMap, Humanitarian OSM etc.