The use of social media to connect with customers is growing among small businesses, according to the results of a semi-annual survey released last week by American Express OPEN, the small business arm of American Express.

Approximately four out of ten small businesses said they used social networking sites to communicate with customers and market their products, according to the Small Business Monitor survey. Not surprisingly, the vast majority of those companies prefer Facebook to other major players liked Twitter and LinkedIn.

This represents a substantial increase from only a year ago, when only one-in-ten respondents reported actively using social networking sites.

The survey attributes the rise of social media usage in part to the economy's slower-than-hoped recovery, as it provides an inexpensive means of marketing and reaching customers.

"Over the last two years, many business owners shelved investment and hiring plans and dipped into cash reserves and personal assets to stem the tide of declining sales," said Susan Sobbott, president, American Express OPEN, in a press release. "Now entrepreneurs are driving more business with existing customers through regular follow-up and better customer service. They're also tapping into relevant and low-cost marketing tools like social media."

The American Express OPEN Small Business Monitor is a semi-annual survey that has been conducted for the last nine years. Its findings are based on the responses of a sample of 726 small business owners and managers of companies with 100 employees or less.