In spite of a flurry of social media-focused content partnerships and continued 9-figure losses for Microsoft's (MSFT) Online Services unit, Bing's market share gains remain meager. comScore estimates Bing's U.S. PC search share stood at 16% in October, compared with 15.9% in September and 15.1% last December. Moreover, Bing-powered Yahoo (YHOO) had a 12.2% share, flat from September and down from December's 14.5%. As for Google (GOOG)? It hit a record high of 66.9%. Bing's international and mobile shares are considerably lower.