When it became clear that Digital Impact Inc. was to be acquired, Kenneth Hirschman, the company’s general counsel, got worried for himself and his staff.

He wasn’t upset that they all might be let go — after all, that’s what often happens to an acquired company’s legal department when the deal wraps up. Instead, Hirschman feared his lawyers would take off at the first whiff of acquisition news, leaving him alone with a mountain of work on a tight schedule, and just when he needed them most.