One in 10 Africans are logging on to Facebook every month, the worlds No.1 online social network said on Monday, presenting a new target audience for advertisers. Facebooks global mobile advertising revenue jumped more than 150 percent in the second quarter, accounting for about 62 percent of overall ad revenue. Knowing that there is all these people now in Africa that you can connect with, that is exciting as well, said Nicola Mendelsohn, Facebooks vice president for Europe, Middle East and Africa. Facebook would be pouring more resources into Africa to understand how consumers use its product and was considering opening an office on the continent in 2015, Mendelsohn said, without saying where the office might be.