The Geocaching search/filtering capability needs to be significantly improved. At a minimum you should be able to alpha search the cache title for a string ANYWHERE IN THE CACHE TITLE (not just starts with) AND also specify a state/country. For the compilation caches you are interested in finding all the "Welcome to" caches in the state of Florida or "Challenge" caches in Oregon.
The GSAK application provides a good example of the ultimate in searching/filtering capability.
The Geocaching search filter should allow the user to specify a COMPOSITE SEARCH/FILTER (i.e. several parameters at once):
cache name contains, cache name starts with the letter, distance (less than, greater than, in between), difficulty (less than, greater than, in between, equal to), Terrain, available status (archived, disabled, active), owner name contains, favourite points (less than, greater than), placed date, cache type, container size, state contains, country contains, GC Code contains.
By allowing the user to specify these parameters the SQL query could be dynamically built and the the results set returned to the screen.
Also allow the results set to be stored as a Pocket Query for download.