User id

The user id in the user settings is the users id number at Geocaching.com. The id number uses the numbers 0-9 and can be converted via a special version of base 31 (base 36 without the letters I, L, O, S and U) to get the coord.info/PR-link to the profile, the same kind of conversion is possible to do for GCcodes to get the id number of the cache.