Facebook\'s chief operating officer was in New York on Monday working to bolster investor confidence with assurances that the social network was intent on making money. Sheryl Sandberg echoed co-founder Mark Zuckerberg\'s disappointment in the company\'s dismal stock market debut in May and said that revenue-generating schemes being considered included charging for upscale services. \"As we increase our investment in monetization, we\'re thinking about premium services for businesses,\" Sandberg said in an interview aired on CNBC. \"We\'ve heard from businesses all over the world that they want more from us, there are things they\'d pay for, they want us to provide, so it\'s an area we\'re starting to explore.\" Facebook had no specific products to announce, but the opportunity is being pursued, she noted. She also repeated Zuckerberg\'s assurance that Facebook sees opportunity in the trend by users to access the service from smartphones or tablets, where the company does not serve-up money making advertising. With the California-based social network giant struggling to prove it can boost revenues, the company last month revamped its \"Offers\" service. The change requires payments, starting at $5 per ad, for the deals offered through Facebook -- making companies pay for what had been free advertising until now. Facebook last week added a feature that lets people send real-life cupcakes, coffee, stuffed animals or other gifts to friends in the social network. The \"Gifts\" program is being rolled out gradually, starting in the United States, and Facebook stands to get a fee for brokering purchases. The world\'s largest social network -- with more than 950 million members -- has seen its stock price sag since its market debut at $38 per share. Shares were $21.96 in after-market trades on Monday.