So Google and Yahoo reps got their first chance to defend their massive ad deal before the Senate Judiciary Committee this morning. According to CNN, Yahoo lawyer Michael Callahan claimed that the deal would give Yahoo the cash it needs to ramp up and seriously challenge Google for dominance in the search ad market: "With all due respect to Google, we have every intention of fighting them and winning - in this and in other areas for years to come." Google suit David Drummond submitted a written statement to the effect that the deal would only streamline online advertising. But Microsoft's representatives showed up as well and did their level best to present the arrangement as illegal and anti-competitive. ""It will lead to an unprecedented level of concentration in search advertising," said Microsoft lawyer Brad Smith. Next up: the House of Representatives this afternoon.