From Lifehacker:
The Stop Online Piracy Act (SOPA) and the Protect IP Act (PIPA) are two bills that sound like they have a mildly positive aim but, in reality, have serious potential to negatively change the internet as we know it. While the Obama administration has come out against SOPA, effectively shelving it indefinitely, the very similar PIPA bill is still alive and well. Both SOPA and PIPA put power in the hands of the entertainment industry to censor sites that allegedly “engage in, enable or facilitate” copyright infringement. This language is vague enough to target sites you use every day, like Facebook and Google, making these bills a serious problem. Here's what you need to know about the bills and what you can do about them.
The idea behind these bills sounds reasonable. They came about in order to try and snuff out piracy online, as the entertainment industry is obviously not excited that many people are downloading their products without payment or permission. The issue is, however, that it doesn't really matter whether you're in support of piracy, against it, or just don't care. The methods are ineffective. Here's what they are and why they're problematic.
More here.