I've actually found the ANI thing to be useful. If someone prank calls you, just forward all your calls to voicemail. When they leave a voicemail, you got their number.
P.S. Speaking of e-mails why don't you ever reply to anything. I think I sent you 4 diffrent things and 2 months latter no reponce. Linear hates you for that too (atleast thats the impression I got from #10).