The page also tells you whether a Senator uses Klout and Twitalyzer (which measures his or her impact on the social web). Neither Sen. Bingaman nor Sen. Udall use these two tools.
While these are the most popular social networking tools, others new ones are gaining in popularity, such as Linked In and Pinterest. (And there are dozens of others that are not used as extensively but are an option to share information).
So perhaps this Senate page will be updated in the very near future to reflect other types of social media. (It will certainly have another type of update in November, since one-third of the Senate is up for reelection, and a number of Senators--including Sen. Bingaman--are retiring).
Of the established social media, Twitter seems to be gaining strong popularity in the congressional campaigns. Many candidates view Twitter as a medium to get out their message (and also to follow what their rivals are saying).
For example, all three candidates seeking the Democratic nomination for the First Congressional District in New Mexico are using Twitter: @Michelle4NM., @MartyChavez, and @Griego4Congress I could not find a Twitter account for Republican candidate Janice Arnold-Jones.
But Republican Senate candidates
And of course, Twitter is a two-way street for anti-hunger and anti-poverty advocates. Not only do we know what the staff of a congressional office is thinking, but we can also use the medium to set up an action alert of sorts to communicate with elected officials. For example, The ONE Campaign recently mobilized activists to contact the chair and the minority leader of the Senate Agriculture Committee via Twitter on the eve of a key vote on the Farm Bill. The tweet was supplemented with a short link to a blog post that contained much more information about the issue.