Well, I've seen it done once or twice. Here are a couple of things that will help.
First, a paper letter sent by regular US mail is worth a dozen or more emails. Even with delays in processing, congresscritters well apreciate the level of interest needed to print, sign, stuff and stamp a real letter as opposed to just sending email.
It's a GOOD thing to encourage people to share their letters in order to inspire others,
but it's a very, very bad thing for people to send a hundred copies of the same letter.
It's also very good to encourage ppl to stay well informed of current events related to your issue and to use them as hooks. "Honerable Mr. Smith, enclosed, please find a clipping from the NYT about ___ private juvenile facility. I spent 18 months in a very similar facility from 1998 - 2000..."
As far as getting people to report their correspondence, there's just no reliable way to do that. However, if you as your own rep's aid, they'll tell you roughly how much interest they've seen for the issue. If you find one day that your call is always directed to the same aid, that's a pretty good indication that the issue has generated enough interest to become an assignment in it's own right.
Keep copies of congresscritter responses and answer them! Even if they're form letters or other forms of brush off, answer what they say to you so they know you're paying attention.
If you want, I'll set up a forum specifically for this purpose which you may moderate.
A wise and frugal government, which shall restrain men from injuring one another; shall leave them otherwise free to regulate their own pursuits of industry and improvement
http://laissezfairebooks.com/product.cfm?op=view&pid=FF7485&aid=10247' target='_new'>Thomas Jefferson