Well, that and the fact that the USPS is ludicrously cheap for what you get -- check out the comparison chart from earlier this year at Postal Sanity (http://postalsanity.com/2010/07/u-s-postal-rates-excel-in-international-comparison/).
That's... fascinating. Lulu's been around for years; it's a self-publishing and print-on-demand company. Nothing wrong with their website that I've ever heard anyone complain about (at least as far as security goes).
According to all the latest reports, there was no truth in any of the earlier reports.