In a continuation of its support for small businesses, American Express announced recently that it would be giving away $100 in free Twitter advertising to small business credit card holders and merchants. Twitter, the social media juggernaut, has developed an advertising platform just for small businesses that will be unveiled late in March.

American Express card holders and merchants can register at to receive $100 in free ads on the new Twitter service. The first 10,000 eligible businesses that register will get the $100; American Express will notify successful registrants in the next few weeks after registering. To be eligible for the giveaway, businesses must have a U.S. billing address and can not have advertised on Twitter before. Entrants are required to sign up for a business Twitter account. More than one account requires separate contest registration. The $100 credit must be used by the end of the year or it will expire.

Ed Gilligan, vice chairman of American Express, said in a press release, "This partnership with Twitter gives our small business owners access to a powerful tool for reaching and engaging existing and new customers."

The Twitter small business advertising program is designed to give owners a chance to reach not just existing customers but a wider audience through the Twitter network. Owners can create and manage unique advertising campaigns, plus they have the ability to tap into Twitter's more than 300 million users.

American Express also hosts Small Business Saturday as a way to support smaller merchants in the U.S. Since 2010, the company has designated Small Business Saturday as the Saturday after Black Friday. For Small Business Saturday in 2011, any American Express card holder that shopped at a qualifying small merchant and spent at least $25 received a $25 credit on their credit card statement.