Lead profiles make it possible to summarize your leads by the data they contain. Lead profiles can only be seen on the new "beta" financial statistics.
To enable profiling for a specific field, edit the field and select the "Profile this lead" checkbox. You may profile more than one field. Profiling a field causes leads to be summarized by the values contained in that field. For example, if you are profiling the "debt amount" field and the "state" field, your statistics will show how many leads have each unique combination of those two fields.
Changing which fields are profiled will not retroactively alter the statistics for leads already collected.