Developers of all sizes now have open access to both calendar and contact data syncing across the web
Google announced today that it will be reopening access to its CalDAV API, and going one step further by adding open access to CardDAV as well. This is a bit of a technical subject, but CalDAV and CardDAV are open standards managed by Google that let developers keep both calendar (CalDAV) and contacts (CardDAV) synced across the web. For example, CalDAV and CardDAV are used by Apple for syncing data on iOS; Microsoft has also pledged to support the APIs since Google's announcement that it is shutting down EAS.
Back in March, Google decided to make CalDAV a partner-only API because it felt that there were only a few select large companies taking advantage of it. Following lots of feedback and information about how smaller developers were looking to make user of the APIs, Google decided that it was better left as an open option for anyone to use. It was only fitting then that CardDAV was opened up as well, and here we are.
This doesn't immediately mean a whole lot for end users, although it does prevent future headaches for developers and companies having to switch and use a different system at some point. Google generally understands the usefulness (and even necessity) of keeping open standards... well, open. Developers will now have unfettered access to both APIs for syncing data between products, and we hope it will stay this way going forward.
Source: Google Developers Blog