Cygnus Business Media, Nielsen Business Media, Reed Elsevier and The McGraw-Hill Companies have banded together to offer greater reach and more efficient media buys for online advertisers. The venture says it’s the largest collection of B2B targets created – more than 200 online properties — including Web sites of publications like Adweek, Aviation Week & Defense Technology and CPA Technology Advisor. BBN will reach roughly 10 million unique visitors a month.

“BBN gives advertisers unparalleled access to reach decision makers across the entire B2B spectrum with one large-scale purchase, through four of the industry’s largest and most highly respected publishers,” said David J. Moore, CEO of 24/7 Real Media, Inc., in a release. “We continually innovate in order to deliver more effective targeting and broader reach for our advertising partners, and have developed the preeminent network in a number of verticals such as B2B.”

BBN joins 24/7’s crowded field of digital media offerings, including more than 1,500 sites that reach 150 million unique viewers per month. BBN will be using 24/7’s Open AdStream for the targeting and delivery of ads to Web sites.