Google mapping can handle up to around 2,500 results. PHP can sometimes cause a problem with timeouts past 1,000 entries on a single map. We have succesfully tested beyond one thousand entries, but that depends on the server at that point. We have given the option of limited SOBI2 Category results by State or Province, and on most installs that keeps the number of results by Category down to a manageable level of 1,000 or less. Keep in mind that a user is unlikely to be able to process that kind of data. The map will be very crowded at that point, so a better strategy is to try and design your SOBI2 directory so as to return more refined data.