Two notes--

First, these amendments are to the Federal Rules of Civil Procedure, not the U.S. Code (our national statutes). Accordingly, they effect all litigants in federal civil litigation. That will include individuals, not just companies. So, if you ever sue or are sued in federal court (relatively common--if you are suing for over $75K and the opponent lives in another state, you can likely get into federal court as opposed to state court), this rule will apply to you.

Second, the duty of retention on electronic documents is currently unclear. As is (and IANAL (yet)), under the federal rules, you have no general duty to preserve documents if you have no reason to believe that the documents will be used in litigation. Its only once you realize that you've screwed up and are likely to be sued that you need to start preservig documents. (Caveat--there may be some specific rules that I am not aware of that require a short-ish (two-year) retention period for some documents, especially documents relating to securities). So, in effect, what this rule says is you now have to hand over your IMs if they are saved, not neccessarily that you need to be saving your IMs forever,