Although the revised policy ensures searches will be completed in a "timely manner" (up to 30 days) and that travelers will stay informed about the search's progress, travelers crossing the border might want to consider a few things.
Officials can still seize any device (including MP3 players or flash drives) and look at any file on it (including Internet browsing history) without giving any reason.
The Association of Corporate Travel Executives (ACTE) believes agents take laptops, make an image of the hard drive and then return the laptop to its owner in the mail. Any copied files could be stored "indefinitely." (Imagine what the Border Patrol's iTunes Library will look like after "indefinitely" storing DRM-free music from several dozen searches.) The ACLU is also taking a dim view of the DHS policy, and is challenging it in court.
For the moment, though, it's smart to be prepared. Although the DHS's exact procedures are unspecified, the department's new policy states when travelers are subject to a search, agents will provide them "with clear and concise material informing them of the reasons for the search, how their data may be used and detailed information about their constitutional and statutory rights."
If you're traveling for business and have important files you'll need on your trip, it wouldn't hurt to save them to multiple locations so you aren't left without them. Better yet, use Google Docs or another Internet-based storage system to ensure your private information stays private.
In the case of a search, ACTE recommends you inform the agent that you have sensitive information on your computer. Try to get your concern noted in writing; at least, be sure to express it verbally. ACTE says this will help you retain more legal rights for registering your concern.
Although these searches don't occur very often (the Border Patrol looked at around 1000 laptops and searched 46 laptops in-depth in the past ten months) the best bet for travelers concerned about privacy is to leave unneeded electronic storage behind.