About that Twitter ad platform that was supposed to launch at South by Southwest but never materialized there ... Well, co-founder Biz Stone tells CNBC that “later this month (we’ll be) revealing exactly how we plan to make a sustainable source of income so we can build a business.” He likely means next month—since that’s when Twitter has scheduled its Chirp conference, which includes “monetization” on its agenda. How exciting! We’ve been waiting so long! The only hint Stone gives: “We’re going to roll out something that we think is appropriate for not just Twitter users but also for the ecosystem. When we develop this monetization platform it’s not just going to be for us. It will actually extend to all these apps that are out there everyone is using.”