Irvine-based YouMail, the provider of enhanced voicemail apps and other telecommunications services, said Thursday that it has now answered two billion calls. The firm said it has doubled its call volume since July of 2011, when it hit an earlier, one billion call milestone. YouMail provides a set of enhanced voicemail services, including personalized voicemail messages for different callers, transcription of voicemails, voicemail recipts, and much more. The firm says is now has 3.5 million registered users of the service. YouMail is venture backed by VantagePoint Capital Partners, the Tech Coast Angels, the Tech Coast Angels ACE Fund, Siemer Ventures, and CrunchFund.