According to a message from the Senate Sergeant At Arms, sent to Senate offices and obtained by NPR, Senate.gov saw a massive increase in requests for two hours following Obama's speech, resulting in many constituents being unable to access it.
"We are again experiencing peak loads today and many sites are sluggish and may at times receive errors," the note said.
The web servers for Congress members such as Speaker of the House John Boehner (R., Ohio) were taken offline for several hours Tuesday. Sen. Jim DeMint (R., S.C.) and Rep. Michele Bachmann (R., Minn.) also found their websites affected.
Thousands of constituents hitting the web to contact their representative, all at the same time, turns out to have the same effect as those denial of service attacks we often write about.