That's a stressful question even in the best of times. At both companies involved in a merger, just about everyone's job becomes sharply redefined as company missions and corporate cultures change.
Cherished goals perish entirely.
And every public statement is scrutinized by employees and customers for hidden meanings. Now take all of those challenges and stir them into the current tumult of the Internet economy. There's no segment I can think of where there shouldn't be some kind of roll-up or consolidation. Even when an Internet CEO can't see the arguments in favor of a merger, venture capitalists, other big shareholders, and even customers are more and more likely to press the case for combining resources. None of them want to watch as a host of minor contenders limp along, unable to create anything big or lasting.