Back in November, when MSNBC began using “the power of change” as a tag line for the network, conservative critics howled angrily, citing the echo of President Obama’s rhetoric as further evidence of MSNBC’s liberal bias. But despite being dragged through the mud in right-wing corners of the Web, during recent months, the MSNBC marketers have, in a sense, flipped the proposition: Being associated with the Obama movement, they clearly believe, will be good for business, not bad.