SAN FRANCISCO (Reuters) - Facebook Inc is on course to generate $1 billion in revenue this year from social gaming, according to Kevin Ryan, a leading Internet entrepreneur and former chief executive of online advertising giant DoubleClick. (http://feeds.feedburner.com/~ff/reuters/topNews?d=yIl2AUoC8zA) (http://feeds.feedburner.com/~ff/reuters/topNews?i=SuIzDN3J300:UAqC3iLjfNk:V_sGLiPBpWU) (http://feeds.feedburner.com/~ff/reuters/topNews?i=SuIzDN3J300:UAqC3iLjfNk:-BTjWOF_DHI) (http://feeds.feedburner.com/~r/reuters/topNews/~4/SuIzDN3J300)