Smartphone sales worldwide continued to balloon in the second quarter, according to research firm Gartner. Smartphone sales jumped 50.5 percent in the quarter compared with last year, more than three times the growth of the overall handset market. Importantly, the firm's latest report shows that Google's Android platform is gaining ground on its rivals, and surpassed Apple's (NASDAQ:AAPL) iOS in terms of market share. According to Gartner, Android's market share climbed to 17.2 percent in the quarter, up from 9.6 percent in the first quarter and 1.8 percent in the year-ago period. Meanwhile, Symbian, which is used by Nokia (NYSE:NOK) and other vendors, saw its market share fall to 41.2 percent, from 51 percent in the second quarter of 2009. Research In Motion's (NASDAQ:RIMM) BlackBerry platform captured 18.2 percent of the global market, down from 19 percent in the year-ago quarter. Apple's iOS platform grew its share to 14.2 percent, up from 13 percent in the year-ago period. Article