I like taking a step back and looking at supposed market euphoria. The world has been seeing some very large takeover / merger deals. Dell and HP's bids for 3Par, Rio Tinto's bid for Potash Corp., United and Continental's merger, Intel's acquisition of Infineon's wireless business... My examples are not many but the trend is towards consolidation.
Something that an M&A guy from Brown, Gibbons and Lang once said: Synergies always account for layoffs. Layoffs in an economy that is already depressed and has a 9.5% (official) unemployment rate? Hmmm... Makes one think of mergers as a sign of confidence in the economy or upcoming stagnation.