Android Police, Google Search 3.3 has code in it that mention a new "inferred event". This means that if you mention an event in an Gmail message, Hangout chat, or maybe even a Google+ post, Google Now would then ask you if you want to add that event to your Google Calendar.According to the code hounds at
This could certainly be a very helpful tool for those out there who are somewhat forgetful about plans that have been made. The benefit to Google (because nothing comes for free) is that Google might learn more about where you will be (and send promotional offers) and who you will be with, which is good relationship data that is more Facebook's domain.
As usual with code reading, there is no guarantee that this feature will make it out to everyone, but it seems like a solid idea, so we would expect it to eventually be a reality.
source: Android Police