The slightly longer version is that it is a bill designed to allow companies to share data with other companies or governments with less hassle, like the hassle of asking or even informing the person who's data is shared. The full title says it nicely: To provide for the sharing of certain cyber threat intelligence and cyber threat information between the intelligence community and cybersecurity entities, and for other purposes.
One interesting thing has popped up in the news, it's that Facebook supports CISPA. Here are some other letters from some brave companies who support CISPA. In Facebook's case I can totally understand their view, their whole business is based on user's data. How could they not support this ?
Now the expected thing to do, if you are interested in privacy and that sort of thing, is to spend hours reading boring legislative crap until your brain starts pouring out of your ears. However, I really don't care this time. This might sound selfish or just lame, but I don't feel very affected by this. I don't have personal data on third party services (or ones I can't trust).
The real reason I don't care is not because I feel covered, it's because many of those that aren't covered do not care. Seriously, so many people believe that the practicality of having an email provider that let's you "star and tag" emails and the convenience of keeping up with friends just by clicking on their name outweighs any reason for concern, since years.
So if you use such services, and again disagree with this sort of legislation then it's your problem to solve now.. You can delete your account(s), write to them or just hope it will go away magically.