MSN Money columnist Michael Brush takes a look at the search space from an investment standpoint and says the exuberance is justified. There’s a very fine line between exuberance and “irrational” exuberance, a line that is quite hard to draw. Clearly the indications are quite healthy, as my last post points out. And we’ve seen irrational behavior in the past, so (I hope) we’ll hold ourselves back this time. If nothing else, many of us just don’t want to go back there again. Once is enough.