Well its not as one sided as you think. Take, for example the sites such as rapidshare and megaupload that routinely share terrabytes of copyrighted material.
If you find your copyrighted content on those sites, you can email them a DMCA takedown that MUST include your phone number, your physical address and other contact details.
Note that megaupload do not provide everyone with their direct contact number, and the people actually uploading the copyrighted content are 100% anonymous.
If you are luck,y after 48 hours the site might remove the content, taking no action whatsoever against the uploader.
Within a few hours, the copyrighted content is uploaded yet again, and the whole process starts again.
All the time, the copyright holder is the one who is giving out their personal information, and the hoster and the uploader remain safely immue to any possible comeback.
nice business model, and one that the DMCA does almost nothing to impact whatsoever.
People who criticise the DMCA for being too harsh have likely never used it, or been on the receiving end. Its a very weak piece of law in cases such as these. (The DRM-related aspects of the law are different, and total overkill however).