Don't know what "Congress" means? Congress is defined in Article I, Section I of the Constitution as consisting of "a Senate and House of Representatives." Note that the word is "Congress"; not "Government", "States", "Cities", or "Websites on the internet".
That means that the first admendment applies only to the United States Congress. It doesn't apply to Wikipedia or Slashdot, or any other website on the internet. It doesn't apply to clubs. It doesn't apply to any other country. Strictly interpreted, it doesn't even apply to the states, counties, or city governments (though there are other laws that do, such as Admendment 14).
That's why it's perfectly legal for a school in Hartford, Conn. to adopt policies that fine students for swearing. That's why it's legal for a website to filter out expletives.
The debate over "Can speech be abridged?" is not the true debate. Of course it can be. The true debate is "Who can abridge speech?".