What Yglesias said.

A lot of people I know are skeptical of the value of calling or writing your member of Congress. After all, why would members of Congress care about such things when scientifically valid opinion surveys are available and few members face competitive elections anyway? Surely, congressional action is determined by some combination of public opinion as measured in polls and corruption via lobbyists. So if members don’t do the popular thing, it must be because the system is corrupt. I doubt it. For one thing, it’s unquestionably the case that members of Congress dedicate a lot of staff time to fielding phone calls and reading and coding pieces of mail. And anecdotally, things like the huge “letter gap” over the Waxman-Markey energy reform bill had a huge psychological impact on the Hill. Then you have research like this. So I do wish everyone would say to themselves, “If I care enough about this issue to complain about it in conversation, then I’d better care enough about it to get in touch with the elected officials who represent me.”

Several staffers told me that until we started calling and writing about the Affordable Care Act, almost every call they got came from Beck fans screaming about crap like death panels and the gold standard. The only other feedback that most of them had to work with was CNN replaying clips of Barney Frank debating whether to give up. Congress jumps at every rightwing whim at least in part because their media does an excellent job motivating a pissed-off rabble to phone their Reps. This is not even a bug – democracy should work like that. Congresspersons must respect feedback from constituents. It is their job.

Do you care about an issue? Don’t complain about it on a blog to people who already agree with you. Pick up the phone* and tell it to someone you voted for (or against)**. Then complain about it on a blog.

(*) To multiply your impact ten hundred fold, send a hand-written letter. Even Senators from big states either read or at least hear about every non-typed letter that they receive. A phone call or a fax will at least get logged. Email has zero impact. Zip. Nada. If you absolutely have to write an email, save time and shout at your cat.

(**) This part matters. Unless you vote in Connecticut Joe Lieberman will not care what you think, no matter how loudly you think it. Nor should he care. If your only choices are Republican then call and tell them they’re schmucks. Trust me, it is cathartic.

***Update***

Duncan notes that staffers like and don’t like different kinds of feedback. In my experience their favorite kind of feedback is specific, succinct, polite and not particularly loud. Say where you live/vote, name the issue, state your position and tell the volunteer what you want Representative X to do about it. Then wish the person a good day. Other stuff sounds more important than it is – instead of telling staffers how big your club of like-minded friends is, have your friends call.

Whether the office ‘likes’ feedback (whatever that means) is really less important than whether or not they respond to it. I doubt that moderate Republicans ‘liked’ the screaming loons who forced them to line up behind Paul Ryan’s suicide pact.

***Update x2***

From commenter DXM. Bolding mine.