The Super-human Registration Act (SRA or sometimes SHRA) - was legislative bill which was passed into law, enforcing the mandatory registration of super-powered individuals with the government. Supporters and critics debated between the rights of the individual (to freedom of action and expression etc.) on one side versus the rights of society at large (to safety from danger or harm) on the other. See also Registration Acts
When the topic of the original Super-human Registration Act was debated the issue was explored in a national security context, with the utility of such a law being challenged. The Fantastic Four went to Congress where a committee was investigating whether a SRA, similar in its provisions to the already in effect Mutant Registration Act, was required for Super-heroes (the MRA only covered individuals who had their powers inherently at birth, not those who acquired their abilities artificially in later life).
In his testimony and in evidence he presented to Congress, Mister Fantastic argued that a Super-human registration Act was unnecessary as Super-humans had been largely effective and trustworthy in their actions and government regulation would have only stifled their ability to protect the world. He argued that those individuals who were likely to act irresponsibly with their powers were likely to be super-villains and thus would not be candidates for registration anyway.
As the topic was debated he and his teammates were continually attacked by random super-villains whom they easily subdued, though it is unclear if this helped or hindered his arguments. In his final point concerning the lack of any workable definition of super-human Richards demonstrated a device that scanned a human for physical and mental capabilities and compared those to the national average and marking 'significant outliers', proving several regular humans, including committee members, to be superhuman according to those definitions. The proposed legislation was abandoned and registration of super-humans was not sought in the United States at that time.
1993 Canadian Super-powers Registration Act
A similarly titled Super-Powers Registration Act was later passed by the Canadian government. Introduced by a minister of the Canadian government called Robert Hagon, the Super-powers Registration Act was part of a complex plot engineered by the Master using the alias "Joshua Lord".
The terms of the act entailed the government employment of all super-powered individuals, including mutants, who were then enlisted in one of the government Department H "Flight" programs such as "Alpha Flight" and "Gamma Flight". The Act was controversial and resulted in the disbandment of the Canadian government's super-teams (the various "Flights") The Canadian SRA was never explicitly repealed or overturned, however it is no longer mandatory.
Super-human Registration Act
Interest in the concept of the act was revived, following the events of "M-Day" and the sudden dramatic fall in the Mutant population, the U.S. government again considered a Super-human Registration Act and Spider-Man and Iron Man traveled to Washington D.C. to discuss the issue. Iron Man initially opposed to the idea, while Spider-Man was unsure of his opinion. 
Iron Man attempted to persuade his Illuminati colleagues to support the SRA in order to defuse it. Iron Man predicted that some super-human or group of super-humans would eventually make a mistake that will cost hundreds of lives. After such an event, he went on to predict, the government would inevitably rush to make an example of someone, or everyone, in the super-human community by passing legislation that would be even more restrictive or persecutory towards them then the proposed SRA. By supporting the Act before it was passed, he suggested, he and his fellow Illuminati might have been able to help avert such possible future tragedies and also, by becoming a part of the process, help moderate the legislation so that it would have the minimum possible negative effect on the super-human community. 
The first part of Iron Man's prediction was proven accurate when a conflict between the New Warriors and a group of super-villains ended with a massive explosion which killed over six hundred people, sixty of them children. The public outcry that followed this event led the government (with the support of Iron Man and other Illuminati such as Reed Richards) to quickly enact the SRA.
This led to a major schism and conflict among the super-heroes, with one side (led by Captain America) opposed to the SRA resisting registration and the other side (led by Iron Man) supporting registration and trying to enforce the new law.
The SRA was abolished after the siege on Asgard.
Terms of the Registration Acts
The Act required that super-powered individuals surrender their real names to the government (but not the public). This obviously entailed the loss of their secret identities.
It enabled the government to monitor all powered individuals and was drafted to facilitate the government's licensing and/or employment of individuals who were actively using their powers. The powered individual had to fulfill some requirements or meet some criteria before they were allowed to fully use their abilities and gain legal authorization to continue to use their abilities to fight crime. Government employment was not mandatory, though it was available to those who wished to take it.