During Google's I/O Developer Conference, Google announced that its Cloud Messaging push notification service now supports sending push notifications to iOS devices. In addition, Google now allows developers to set up so-called 'topics' within their apps so users can choose the subjects they are interested in getting notified about without developers having to set up any special infrastructure.
When Google launched Cloud Messaging, the service only focused on Android devices, but these days, it also supports sending push notifications to the browser (and, in the most recent versions, that's linked to the native notifications services in OS X and Windows 8). More on this at TechCrunch.
Today's I/O Developer Conference has consistently focused on making their SDK builds for not only Android but also iOS. Noted above is the SDK announcement regarding Google's Cardboard 3D viewer for all smartphones including Apple's iPhone.
Earlier we reported on the new Google Photos app for iOS being made available later today for iOS users. Google is obviously taking the road that Microsoft is taking by making sure that their software is cross platform. Will Apple introduce iTunes for Android in June to continue this happy trend? Only time will tell.