LDAP folks: Who uses altBaseDN ... and why? =)

Hi folk! I’d like to get a feel for why folk are using altBaseDN … or -if- anyone is using it? Please let me know if you are using it and what you are using it for. I have a suspicion that the reason folk are using it is because we’re not offering enough config options for some things, but I could certainly be wrong. =) Thanks!