extra field - a date for each user.

[ddausch]

I'm searching for a hack, which gives the possibility to fill in - in an extra field - a date for each user. This field (we could name it "userstate") should only be seen throgh the AdminCP. I would like to fill in this field a date and also would like to be able to get a list, sorted by these dates/field.
Is there any Hack existing which is providing these specific needs?

thx

[NTLDR]

Just add an extra user profile field in the acp which users can't view or edit.