The average contribution to Obama in September was just under $86. And federal law only requires the disclosure of identifying information for contributions in excess of $200. Campaigns must keep running totals for each donor and report them once they exceed $200.
The Federal Election Commission says the Obama campaign has reported well over $200 million as coming from contributions of $200 or less. Only a small portion of that sum is attributable to donors the Obama campaign has disclosed.
No presidential campaign has ever before received such a gargantuan sum of money from unidentified contributors.