"Little evidence exists thus far that corporations are rushing into the fray [of campaign spending]" - Time
This line from last week's Time Magazine struck me because it comports to my intial reaction to the Citizens United ruling. I thought the histrionic reactions were ridiculous because I expected the ruling to have minmial effect. This is not really my field of study anymore, but all the research I am aware of argues that previous limits against corporate campaign spending were not binding because corporate spending was so low (Ansolabehre, de Figuereido, Snyder), that what spending there is does little to sway how a politician votes (ibid, and the empirical tests of Grossman-Helpman) and that money is largely not very effective at buying votes (Levitt). (For those political scientists out there, please correct me if there are other papers I should be aware of)
Thus it makes perfect sense that the ruling would have minimal effect on corporate spending despite all the media and pundit bloviation. There has been a lot of spending by wealthy individuals this season, but as Time noted, this is nothing new, for example George Soros spent a ton of money attacking Bush in 2004. Perhaps the ruling made wealthy individuals think they could hide their spending more easily but that also largely seem not to have been the case as intrepid reporters have been good ferreting out the sources.