At a session I did early this weekfor a group of people heading up to the hill to lobby Congress, someone asked the very clever question "what do the staff people do with all the paper we leave behind?" Good question, right? Who wants to lug around reams of paper if they don't have to?
The GR staff for the group pointed out, very correctly, that Congressional staff are people, too. Some will keep it, some will throw it away, some will keep it for a short period of time then throw it away -- they're all over the map. The point was also made that many staffers these days are all about electronic versions of materials. If you store the materials in electronic version on your website, in many ways you're doing their filing for them! All they have to do is bookmark it (i.e., stick a label on it) and they're done!
My experiences as a former staff person and friend of current staff bears all this out. The more materials you have available on the web, the more your stuff will be read. Likewise, keep in mind that staff have very limited room in their cubicle space. If they can keep anything you give them, it will probably be one page. But there is infinite (or near infinite) storage space on the web -- help them keep track of all the issues by making your site as accessible and friendly as possible.
Another approach staff take? Sometimes they'll hold on to the paper you give them for a couple months -- just to see how serious you are about what you asked for. See, if you don't come back a-callin' (or a-emailin') within a couple months to follow-up on what you asked for, you probably weren't that serious. And that's when your materials are likely to be dumped in the round file.
One last tip: consider providing your very brief, very concise follow-up materials in plain old, unfancy manilla file folders. Then all staff have to do is stick the folder in their filing cabinet. Much easier to hold on to that way.