"Digital Watermarking and Metadata
Metadata is a secondary, hidden, layer of descriptive information embedded into a digital file. EXIF is the format for metadata in photographs embedded into digital files by your camera or post-processing software. EXIF data contains information on camera hardware and settings like aperture, ISO, shutter speed, and even GPS location. You can even add logos, contact information, licensing restrictions and copyright registration information to metadata.
We advise photographers to add as much information as possible to their EXIF files. Complete EXIF information is helpful because it identifies you as the photographer who created the photo and provides information about who to contact to license the work. Metadata also functions as a digital copyright notice that, if removed, triggers a violation of the DMCA.
All popular photo processing software titles have tools to edit metadata in a single photo or in batch mode. Free and open source software is also available."
Source: http://www.sriplaw.com/mls-really-photos-pt-4/
1x.com please stop the violation of the DMCA (Digital Millennium Copyright Act, http://en.wikipedia.org/wiki/Digital_Millennium_Copyright_Act), don't remove the EXIF and IPTC metadata from the image files!