Thanks, Peter, for the reply.

survey:date=yyyy-mm-dd - Use this tag when the location has been physically verified in person by you.

check_date=yyyy-mm-dd - Use this tag when the location has been verified through local knowledge or extrapolation (for example, by checking the company website).

check_date:currency:XBT=yyyy-mm-dd – Use this tag when a verified purchase in Bitcoin has been made. Most of these transactions are recorded on the BTCmap.org website or through various Android apps.

Never delete data/tags from OSM if you do not know what they are used for.

Happy mapping,

Edwin
