With the invention of xerography (commonly known as photocopying), it became practical for the individual to quickly copy any printed material without losing information to the copying process. Though not economically feasible to copy large works using this technology, it was sufficiently economical for many to copy only those portions of a work that they needed -- leading to a potential loss of revenue for publishers. The "fair use" terms were written into copyright law in order to "decriminalize" what was, by that time, a widely adopted practice for gaining personal access to information. By the 1970s, the invention and wide use of BetaMax and VHS led the courts to extend "fair use" to allow "time shifting" of copyrighted material widely available over the airwaves -- which were placed in the public domain by Congress in 1934. However, as with xerography, the copy was of lower quality than the original and thus was easily distinguishable from the original. This kept illegal copying (essentially, copying for a profit) below the threshold necessary to threaten the economic interests of the parties involved (authors, publishers, and users).
The DCMA (and with it DRM) is perceived by most users today as a way to protect corporate interests -- not those of the authors of the intellectual property. The low cost of blank media as compared to the high cost of copyrighted materials exacerbates the perception that the only ones profiting from the protection of intellectual property rights are corporate interests.
Using widely available technology, it is now possible to make perfect digital copies of copyrighted material. These copies are indistinguishable from the originals. Coupled with the perception that some nameless, faceless, corporation is ripping them off, many turn to peer-to-peer networks for convenient access to these copies rather than visiting their local retailer. The operators of those peer-to-peer networks have just as much of an ethical (and now legal) obligation to protect the intellectual property rights of authors as do the publishers who still represent the bulk of the authors publishing today.
My objection to the DMCA (and DRM in general) is my perception that publishers, given the opportunity, will limit the choices of those with legally obtained intellectual property. I do not want to be told that I cannot put my ebooks, music or videos (which I bought and paid for) on my PC or my iPod -- or in any other form convenient for my use or my family's use.
I suspect that many share that view and, for that reason alone, many will turn to technology developed by the unscrupulous in order to free themselves from contrived schemes intended to thwart the pirate-for-profit but have the opposite effect -- of turning otherwise honest users into "pirates" themselves. Often, the users of these peer-to-peer networks may not even realize that the tools made available to them for free are allowing them to do something illegal -- and punishable by fines or jail time!
This decision by the Supreme Court places the responsibility for the use of peer-to-peer networks squarely on the shoulders of the providers of those networks -- where it belongs! No provider can control how their services are being used all of the time but this decision places them on notice that if they have a reasonable expectation that their network is being used for illegal purposes, they have an obligation to take action to prevent those illegal acts -- or face prosecution or litigation for damages.
As for the DMCA -- and DRM in general -- corporate interests can go a long way to changing the perceptions of many by changing their attitudes. Rather than trying to thwart the very digital technology they have come to rely on for their livelihood, and inconveniencing their legitimate customers in the process, the RIAA, the MPAA, and other holders and publishers of intellectual property should be leveraging this technology to make these materials more widely available at attractive prices so that piracy is no longer an attractive option to the casual user. iTunes and eReader.com are just two excellent examples but they are only the beginning.