EBay Inc posted a 13 percent rise in quarterly revenue, as better-than-expected results from its fast-growing PayPal division helped to overcome increasing competition from Amazon.com Inc and a well-publicized cyber-attack that exposed customers data. Ebays stock has fallen more than 8 percent since April, hurt by a cyber-attack disclosed in May that compromised data for some 145 million customers; Some analysts said a change in Google Incs algorithm in the quarter may also have pushed eBay results lower in search rankings, leading to slower traffic. Several investment brokerages downgraded their forecasts for eBay ahead of Wednesdays results.