Campaign Spending by Third Parties

Last year's Citizens United v. Federal Election Commission allowed corporations to give unlimited donations to third parties running ads in a campaign.  If that third party is running only issue ads (as opposed to promoting a candidate) it does not have to tell where the money is coming from (therefore getting around the 30/60 requirements of McCain-Feingold). So here is an article explaining that and from now until the election you can go here and see the top interest groups, where they are spending and which party's members they support.  It will be updated weekly until the election.