BuddyPress.org

I just went through this so I am a voice of experience.

Each additional profile field you add in the profile field setup is added to the xp_bp_xprofile_fields table. By default, there is only one field filled in on the wp_bp_xprofile_data table, which is the “full name.” Once you or someone else begins to add their additional information and hits save, the data table will expand and in a strange albeit normal way. The id of the user, say ‘2’ will be listed repeatedly, as they have multiple pieces of information stored. The id of the table counts sequentially, so you’ll begin to see that number grow exponentially.

Hope that helps.

Brian