Usage of "Site source" field on Customer sites page ?

Hi,

We have one query, On Customer sites, we have one Oracle standard field named "Site source". Does Anyone know relevance of this field, what information this field stores and how to populate data in this field. We tried creating couple of sites for few customers but could not populate data for this "site source" field. We also checked table "hz_party_sites" but no column with similar name.

Any pointers will be helpful.

Regards,