If you had any remaining doubt as to whether and how much this is happening, wonder no more. Two projects have shown that Comcast and Road Runner consistently engage in substantial, discriminatory slowing or throttling of internet traffic (euphemistically referred to as "shaping") both to and from users, and that "Comcast, Road Runner (from Time Warner Cable), and Cox all use downstream shaping." (More at Boing Boing)
They claim they only do it to help manage traffic volumes. But there are many examples of known, wrongful censorship of political or other content, within as well as outside the U.S.; see, e.g., here (Comcast and/or Symantec blocked all e-mails containing URL of site calling for investigation into whether Pres. Bush committed impeachable offenses in connection with the push to invade Iraq, successfully reducing the impact of activists' efforts), here (AT&T censored Pearljam concert by deleting lyrics criticizing Bush), or here (Mindspring and OneNet Communications, successively, blocked site hosting Nuremburg Files).
As Lawrence Lessig stated in a recent article, "The innovation commons of the Internet threatens important and powerful pre-Internet interests. During the past five years, those interests have mobilized to launch a counterrevolution that is now having a global impact."
Bad enough that, as "Napoleon said . . . it wasn't necessary to completely suppress the news; it was sufficient to delay the news until it no longer mattered." But worse, ISP's can suppress any info they choose in ways that make it unlikely that many users will ever become aware that anything's been filtered out.
And as stated at sp!ked-IT with reference to Wikileaks, among others, "when an ISP removes [or blocks] content, it invokes the cyber equivalent to the death sentence. When an ISP acts it can effectively destroy a business or censor a political campaign, by making access to that website impossible.
If you agree that protecting the internet as a source of uncensored political information is one of the most urgent issues of our time, please spread the word about it.