The Sideline Offensive: Company A acquires Company B. Companies C, D and E should view this as their opportunity to strike.

The relative calm found on the sidelines can often prove to be a welcome respite - especially in a tentative and uncertain market such as the one dealmakers are facing today.

As of March 1, deal activity had been more than halved from the $308 billion in transactions inked during the first two months of last year, according to Thomson Financial, with just $147.9 billion worth of deals coming out of January and February.

PE firms dealing with credit weakness are using the pause to attend to their portfolios. Strategics, on the other hand, had a brief window to take advantage, but have since seen that crack shut closed as questions about the economy put company boards on the defensive. Needless to say the sidelines are getting crowded.

All of this doesn't mean companies can't use M&A to their advantage. Indeed, deals will still happen. Witness Microsoft's hostile bid for Yahoo or the consolidation that is starting to percolate out of the airlines sector. But pursuing the "me-too" transactions isn't necessarily where the opportunity lies today. Rather, to some, it's about keeping track of the M&A occurring in a given segment, and attacking the soft spots that might be exposed as businesses and markets transform.

"The best time to jump-start change is when a competitor is involved in a merger," New York University's Robert Lamb tells Mergers & Acquisitions Journal.

Lamb, a clinical professor of management at NYU's Leonard K. Stern School of Business and co-author of the book "Capitalize on Merger Chaos," has studied this alternative take on M&A for years. While such a strategy may seem obvious, Lamb notes it's most often the case that the "opportunity is squandered."

Ten years ago this June, Compaq ostensibly changed the model for the entire computer industry with its roughly $9 billion takeover of Digital Equipment. Headlines screamed about the pressures facing IBM and Dell Computer as a result. Service was supposed to become an issue, as was pricing power over the suppliers. Michael Dell's response, however, was anything but panic. In an interview with Fortune Magazine, he called the merger "a huge gift." And as Compaq moved to integrate Digital Equipment, Dell, the company, fixed its sights on Compaq's enterprise business accounts.

Lamb calls Dell's ensuing advance the …