A quick glance at the latest API house-cleaning from Google might lead you to believe they're discontinuing some of their most popular APIs. The changes to the Google App Engine API and YouTube API, among others, are likely just formalities of moving to a single terms of service. However, there are some APIs marked for deletion by the search giant, including the popular Google Chart API.
The post explains the changes to some of Google's most popular APIs:
Google App Engine, Google Maps/Earth APIs and YouTube API will wind down their current 3-year deprecation policy and will transition to the one-year policy in April 2014. Google Cloud Storage keeps its current one-year policy. To be very clear, we are not deprecating the APIs themselves.
The good news: all these APIs are around today. Bad news: you only get a one year warning now. Of course, that doesn't take effect until a year from now.
For a handful of other APIs, Google removed the deprecation policy completely. That means no notice will be required to discontinue the services. However, most of these don't take effect for three years.