If I embed IPTC data into images that I provide to clients (or anyone else) and assuming they don't remove that data, is it possible to search for the data in that image over the web using google or another search engine?
If it is possible, how?
I looked for image metadata search engine on the web for a long time. Google and Flickr have some limited capability (Flickr restricted to its domains). There are other tools which have been discontinued. Your best bet looking at the future is CameraForensics, from the creators of StolenCameraFinder.