COINTELPRO

Not Internet surveillance per se, but the grandaddy of government surveillance programs, this ran from 1956 to 1971 and included HTLINGUAL, a program that opened and read people's physical mail. It was looking for "subversive" groups -- mostly leftist/communist/social groups, but everyone from Martin Luther King to Albert Einstein got looked at. It was also widely abused, as the Church Committee, organized to investigate illegal actions on behalf of the program, put plainly:

Groups and individuals have been harassed and disrupted because of their political views and their lifestyles. Investigations have been based upon vague standards whose breadth made excessive collection inevitable. Unsavory and vicious tactics have been employed -- including anonymous attempts to break up marriages, disrupt meetings, ostracize persons from their professions, and provoke target groups into rivalries that might result in deaths. Intelligence agencies have served the political and personal objectives of presidents and other high officials. While the agencies often committed excesses in response to pressure from high officials in the Executive branch and Congress, they also occasionally initiated improper activities and then concealed them from officials whom they had a duty to inform.

On the plus side, it was also used to infiltrate and disrupt white hate groups like the Ku Klux Klan, but that's not exactly tipping the balance.

COINTELPRO was officially shut down in 1971, but many of the programs formerly under it continued for decades.

Carnivore

Carnivore was a physical box -- running Windows, no less -- that the government insisted be placed at ISPs, starting around 2000. It contained a pretty basic packet sniffer and a removable drive so that data could be periodically collected. A primary objection at the time was that Windows was sufficiently unreliable that it could deteriorate the quality of Internet access in general. Many also objected to the invasion of privacy it represented.

After a lot of negative publicity, Carnivore was renamed to "DCS1000". By the following year it had been replaced by commercially available equivalents. The program was never officially shut down.

ECHELON

First reported in 2001 but apparently in operation since the 60s, ECHELON's purpose is to monitor and intercept international communication, primarily by satellite, but also undersea cables (by use of "beam splitters" on fibre-optic cables) and microwave links. The program has not been publicly acknowledged by the US government.

Room 641A

Operated from 2003 onwards and revealed in 2006, Room 641A was a facility in an AT&T building in San Francisco fed by beam splitters that could acquire copies of backbone Internet traffic. There were said to be similar rooms at Internet facilities around the country. Again, the program has never been officially discontinued.

DCSNet

Consists of at least 3 Windows software packages called DCS3000, DCS5000 and DCS6000 which collectively allow the FBI to instantly and in real-time perform wiretaps on any cellphone, landline or SMS within the US. Its existence was revealed in 2007 after the EFF filed Freedom of Information Act requests regarding it. It's not clear whether it's still in operation.

PRISM

This week's revelation is that a program very like all the previous programs does all the same things the programs previously did: monitors and intercepts Internet communication, with the intention of intercepting primarily traffic from non-domestic sources for the purposes of counter-terrorism (aka "subversive groups").

You can love or hate domestic Internet surveillance, but there's no credible way you can claim surprise.