About 5 years ago, I worked with some great people at Xerox to produce PS Magazine. Then a few years later I worked with the same folks at Xerox to produce the Parsons Guide to Getting It Right, The Art and Science of Digital Printing. The second book is still available at the Xerox website for sales support.
The first got many dollars worth of ads and trade exposure. I seem to remember that the number was over a 1.000,000 impressions. The ROI was hard to figure since the cost was pretty close to zero, except of course the cost of the ad placements.
If you want more details, get in touch with the folks at Xerox who supplied the interest and focus to get the two projects done. Or if you want to leave a real name, I'll tell you all about it here.