Cue, which recently announced it's shutting down its app, relied on a user's e-mails and social networking info to push time/location-sensitive notifications. Google Now does something similar while relying on Gmail, search, Maps, and other Google services.
Google is fresh off updating its iOS search app to send Android-like push notifications. Apple, meanwhile, has updated its iOS Notification Center (via iOS 7) to provide time-sensitive updates (among other things).
TechCrunch's Matthew Panzarino calls the deal a necessity in light of Google's Now's competitive edge. "Google Now offers a really compelling experience that only Google is churning through enough data to replicate ... There’s just nothing on iOS that compares." He thinks Cue "could be used to make Siri more powerful and aware, notifying you either via push notification or voice."
The Verge's Dan Seifert: "If this Cue purchase is really Apple’s move to take on Google Now, it has a LONG way to go. Google shouldn’t worry, Cue was pretty terrible."