This is not partisan, it applies to either party.
I emailed my Senator about SOPA and got a direct response. The response was that she was in support of it, which didn't make me thrilled but I got a response.
It was sufficiently well thought out and long that I just assume she was inundated and had a canned reply her aids just pasted to everyone and changed the names.
A call may have had more of an impact since fielding a call is, after all, more expensive than an email.
A lot of the emails she received for either side of the issue were probably canned too.
EDIT: I should note I don't know much about the article's point on calling vs. emailing. Even emailing a local politician is probably effective. Just take any amount of time to contact your local representatives, and you'll put your issues ahead of 90% of the constituency.
"And just like that, legislator offices invest in automatic voice transcription technology, eliminating all human interaction."
When it is easy to communicate via a medium, it is also easy to ignore it. Synchronous means of communication have always had more credibility, but as this article infers, it is going away. Too many armchair politicians doing the bare minimum.