Gmail has always been a fairly open mail platform. For years it has freely offered access via POP and IMAP (which is something rival Hotmail only offered relatively recently), which means the service could be used by almost any third party mail client. Google have also been open to any suggestions that might improve the Gmail service through their Labs feature.
Additional third party integration with Gmail has been possible (you only have to look at all the contact import features from sites like Facebook), but these have either been clunky manual procedures that involve exporting contacts to a text file or they require you to supply your email password. Neither option is all that attractive.
Now there is an alternative. Google has added the ability to access the IMAP/SMTP features of particular Gmail account using OAuth:
While it is possible for a user to authorize this access by disclosing their Google Account password to the third party app, it is more secure for the app developer to use the industry standard protocol called OAuth which enables the user to give their consent for specific access without sharing their password. Most Google APIs support this OAuth standard, and starting today it is also available for the IMAP/SMTP feature of Gmail.
The feature is available in Google Code Labs and we have provided a site with documentation and sample code. In addition, Google has begun working with other companies like Yahoo and Mozilla on a formal Internet standard for using OAuth with IMAP/SMTP (learn more at the OAuth for IMAP mailing list).
What this means for develops is the ability to create mashups that directly access the emails stored in a Gmail account without requiring users to submit their password. It gives users piece of mind, and removes the burden of securely storing user’s passwords from developers.
This feature has already been put into practice by the Syphir SmartPush iPhone application, and ReadWriteWeb have reported that the backup service Backupify will announce that it is leveraging the new technology to back up Gmail accounts. With tens (and possibly hundreds) of millions of Gmail users, it won’t be long before we starting seeing more Gmail mashups.