The Protecting Children From Internet Pornographers Act would mandate the tracking of Web browsers' credit card info, IP addresses and other information about their Internet actvity, all in the name of protecting kids from the evils of child pornography. But what does tracking every petty thief's online activity have to do with stopping the spread of child porn?

The bill, officially H.R. 1981, is the brainchild of U.S. Rep. Lamar Smith (R-Tex.) the author of the controversial Stop Online Piracy Act (SOPA). Now that SOPA has been shelved, Smith has moved on to pushing H.R. 1981, a bill the Atlantic magazine called arguably the biggest threat to civil liberties now under consideration in the United States.

The bill is similar to SOPA in that it would place new restrictions on Internet freedom and privacy, and because it has drawn opposition from the familiar cast of characters, from civil rights groups to Internet freedom advocates.

But the Protecting Children From Internet Pornographers Act, which has been described by some observers as SOPA's big brother, is intrusive in ways that SOPA never deigned to be. It is a whole different type of assault on personal privacy and online freedom, and it introduces its own set of constitutional and moral questions.

The following points offer a good primer on the act and what its passage could mean for the future of privacy in America:

1. It would require ISPs to track Web users: If the Protecting Children From Internet Pornographers Act were enacted, it would mandate that ISPs (Internet Service Providers) like Verizon Communications or Comcast track and log data about their users.

The Atlantic provided a summary of what incursions into personal privacy the bill includes, and how they would be implemented if H.R. 1981:

Under language approved 19 to 10 by a House committee, the firm that sells you Internet access would be required to track all of your Internet activity and save it for 18 months, along with your name, the address where you live, your bank account numbers, your credit card numbers, and IP addresses you've been assigned, the Atlantic wrote. As written, The Protecting Children from Internet Pornographers Act of 2011 doesn't require that someone be under investigation on child pornography charges in order for police to access their Internet history -- being suspected of any crime is enough. (It may even be made available in civil matters like divorce trials or child custody battles.)

2. It actually would do some good: Contrary to what some of the loudest critics have said, the act would have some positive impacts. It would aid in law enforcement's fight to curb child pornography several ways. The official summary from the Congressional Research Service states that the bill amends the federal criminal code to prohibit knowingly conducting in interstate or foreign commerce a financial transaction that will facilitate access to, or the possession of, child pornography.

The summary goes on to explain that H.R. 1981 would also increase penalties for major child-porn related offenses by imposing a fine and/or prison term of up to 20 years for the possession of pornographic images of a child under the age of 12.

These provisions would undoubtedly provide useful tools for authorities to use in the fight against the scourge of child porn, but it is the other parts of the bill -- the parts that strip the right to Internet privacy away from American citizens not necessarily charged with child-porn- or web-related crimes -- that have critics raising red flags.

3. Congressional support is growing : As of Dec. 16, federal records show a bipartisan coalition of 40 members of the House had signed on as co-sponsors of the bill. That number is up from just the two who introduced it in May (Smith and Rep. Debbie Wasserman Schultz, a Florida Democrat who is also Democratic National Chairman). With a name like the Protecting Children From Internet Pornographers Act, it's probably not too difficult to get people in contested primaries and tight re-election races to sign on

The bill also has a lesser-known counterpart in the Senate. As was the case with SOPA, the U.S. Senate has its own version in S. 1308, which was introduced by Sen. Orrin Hatch (R-Utah). With only four co-sponsors, support may grow in the aftermath of SOPA's shelving, as the opposition is not yet as strong to this legislation as it was to PIPA (the Protect IP Act, SOPA's Senate counterpart), which 40 senators supported at the bill's peak popularity. Also dubbed the Protecting Children From Internet Pornographers Act, the Senate version is slightly different, but opponents have raised similar concerns about both bills.

4. There is an alternative: Sen. Ron Wyden (D-Ore.) has been a leader in ensuring an open Internet. Last March, Wyden introduced a bill  that would protect children from sex trafficking and support victims of sex crimes. The bill does not, however, require the tracking of individuals' online activity or financial transactions, essentially making it a safer alternative to the Protecting Children From Internet Pornographers Act.

Known as the Domestic Minor Sex Trafficking Deterrence and Victims Support Act, it has 12 sponsors but has been tied up for months in the Senate Judiciary Committee.

5. It's old news: A lot of adjectives can be used to describe the Protecting Children From Internet Pornographers Act, but new isn't one of them. Smith first introduced his bill last May and it languished. It took a back seat as the Hollywood and music industry lobbying machines pushed SOPA, but now has been given new life.