Legal Question in Technology Law in California

Unfortunately, with so many people named or nicknamed "Willie" and the change in appearance after 18 years, this is a tough assignment without more information. Something like a last name, a former street address, etc. would help with the detective work.

It is already possible to match pictures on the internet, and pretty soon you will be able to scan Willie's photo and find out where he lives, his social security number, and his shoe size. Big Data companies like Facebook and Google are not releasing this photo-search technology -- to the general public, and for now -- because they realize it can be used in nefarious ways by stalkers and others.

One thing you could do is set up a Where's Willie page and invite people to contact you if they know his whereabouts.