While the Internet is by far the fastest-growing ad medium, one top buyer says it won't be cutting into TV expenditures anytime soon. But Margaret Clerkin, who helps allocate about $175 million
in Web ad cash at MindShare Interaction North America, says she is more than ready to start spending money on mobile phone ads once the various carriers get their acts together.
"We've seen significant share-shift from newspapers and print to online," she says. "But everything we've seen is that online and TV are the most powerful combination to move brand metrics. People are not giving up their big screens. I haven't seen major share shift yet, and I don't know if there ever needs to be."