A cautious Goldman note could be adding to Facebook's (FB -6.7%) losses this morning. The firm...

A cautious Goldman note could be adding to Facebook's (FB -6.7%) losses this morning. The firm expects shares to "remain volatile over the next few months" due to the giant Nov. 14 lockup expiration and "the market's allergy to supply." Nonetheless, Goldman is maintaining a Buy, and is encouraged by the higher ad rates associated with new ad products. (Barron's column)