Apple's recent filing for the "mood scanner" tool states that it will monitor your "mood-associated" data – everything you browse, share, or view through your mobile device will be used in order to generate information about your current mood status. In addition, this data can be inferred from "a digital media item, a social networking activity", or even "an invitational content item response". The time of day and the user's current location will also be among the factors that affect the "mood scanner". After the tool gathers enough information, it will produce a baseline mood profile. This profile will be used to "deliver content that is selected, at least in part, based on the inferred mood".
If the tool fails to infer your current mood, it will simply ask you how you feel at the current moment. But this can lead to "user aggravation", the application says, so it will first try to define your emotional status by the data it succeeds to collect.
Thankfully, Apple's patent filing states that users will be able to select whether to share their personal data with the tool or not. It is also said that should users "opt out of participation", the mood scanning feature will still work with "a bare minimum amount of personal information", or no such sensitive data at all.
source: USPTO via Pocket-lint