Third party reading your email : Gmail

Google has confirmed that users sending and receiving private emails are read by third-party app.Users who have connected thier third party app to gmail accouts may have grudgingly given permission to read thier messages.
According to the Wall street journal these practices are common and dirty secret.Also google indicated that this practice is not against its policies.it is so surprising that google allows it.

when people install apps like travel app and price comparison,they ask about some permission to read,send ,delete and manage your emaiils.This permission sometimes allows employees of third party apps to read users email. According to Edison software hundresds of emails are reviewed to build a new feature software.

Gmail users must visit the security chechup page to see which and how many apps are link to their gmail acount.
source : bbc news