Walgreen Co.'s (NYSE:WAG) announcement Thursday that it will acquire online personal-care-products retailer Drugstore.com Inc. (NASDAQ:DSCM) marks the latest deal in which traditional chains are scooping up their Internet competitors.

Just last month, on Feb. 17, department store Nordstrom Inc. (NYSE:JWN) said it was acquiring members-only shopping website operator HauteLook Inc. and its hautelook.com site.

Similar deals could be on the way. Legacy brick-and-mortar retailers, by acquiring their online equivalents, not only gain much-needed assets and technology to expand Internet merchandising, but also take out a competitor, help secure their own future and gain certain synergies in the process.

Paul Hurley, chief executive of members-only website operator Ideeli Inc., said the Walgreen deal is further acknowledgement of the importance of selling merchandise online, and a bet on the future.

The rationale behind most of these deals, however, is on a case-by-case basis, he said.

Hurley hesitated to say brick-and-mortar chains lack the expertise or knowledge of how to operate an Internet retailer, stating that some of these chains have very successful online businesses. Yet, in some cases, traditional merchandisers are in need of some of these e-tailers' technology, which is either patented or difficult to replicate.

In other cases, the big-box retailers may need to inject their own corporate cultures with the entrepreneurial spirit, speed and management experience related to the Web of their younger, more nimble online counterparts.

That said, a new wave of consolidation between brick-and-mortar and e-tailers is likely to ensue as the Internet proves to be the one source of rapid growth that traditional retailers can't ignore. Consolidation could simply be the next logical step as legacy brick-and-mortar operations have already launched and developed their own e-tailing efforts and will now seek acquisitions to add to their customer base.

With the valuations and premiums being paid, perhaps it is the kind of dealmaking Internet retailers can't ignore either. Walgreen's offer of $3.80 in cash for each share of common stock for an equity valuation of about $429 million is a 113% premium over Drugstore.com's Wednesday closing price. Nordstrom's offer of $270 million in stock for HauteLook was a valuation of about 3 times revenues, according to an industry banker.

Walgreen, however, intends to initially run Drugstore.com as a separate business. While not commenting specifically on Walgreen, Hurley said that in some situations integration can be difficult to achieve for traditional retailers.

The big-picture view is that retailers need to increasingly see the online and the brick-and-mortar worlds as a whole, and not as separate. That's one challenge that dealmaking alone will not overcome.