This advertising practice has been significantly criticized by privacy advocates with concerns over unlimited data retention, ease of monitoring by third parties, users of other email providers not having agreed to the policy upon sending emails to Gmail addresses, and the potential for Google to change its policies to further decrease privacy by combining information with other Google data usage.

In June 2017, Google announced the end of the use of contextual Gmail content for advertising purposes, relying instead on data gathered from the use of its other services.

[6] On April 1, 2004, Gmail was launched with one gigabyte (GB) of storage space, a significantly higher amount than competitors offered at the time.

Georges Harik, the product management director for Gmail, stated that Google would "keep giving people more space forever.

[17] The Gmail user interface initially differed from other web-mail systems with its focus on search and conversation threading of emails, grouping several messages between two or more people onto a single page, an approach that was later copied by its competitors.

Majorly redesigned elements included a streamlined conversation view, configurable density of information, new higher-quality themes, a resizable navigation bar with always-visible labels and contacts, and better search.

In addition to customization options, the entire update can be disabled, allowing users to return to the traditional inbox structure.

Other updates include a Confidential mode, which allows the sender to set an expiration date for a sensitive message or to revoke it entirely, integrated rights management and two-factor authentication.

[36] As of March 2015[update], the Gmail interface supports 72 languages, including: Arabic, Basque, Bulgarian, Catalan, Chinese (simplified), Chinese (traditional), Croatian, Czech, Danish, Dutch, English (UK), English (US), Estonian, Finnish, French, German, Greek, Gujarati, Hebrew, Hindi, Hungarian, Icelandic, Indonesian, Italian, Japanese, Kannada, Korean, Latvian, Lithuanian, Malay, Malayalam, Marathi, Norwegian (Bokmål), Odia, Persian, Polish, Punjabi, Portuguese (Brazil), Portuguese (Portugal), Romanian, Russian, Serbian, Sinhala, Slovak, Slovenian, Spanish, Swedish, Tagalog (Filipino), Tamil, Telugu, Thai, Turkish, Ukrainian, Urdu, Vietnamese, Welsh and Zulu.

[41][42] The modern AJAX version is officially supported in the current and previous major releases of Google Chrome, Firefox, Microsoft Edge and Safari web browsers on a rolling basis.

[56] In November 2014, Google introduced functionality in the Gmail Android app that enabled sending and receiving emails from non-Gmail addresses (such as Yahoo!

[57] In November 2016, Google redesigned the Gmail app for the iOS platform, bringing the first complete visual overhaul in "nearly four years".

The update added much more use of colors, sleeker transitions, and the addition of several "highly-requested" features, including Undo Send, faster search with instant results and spelling suggestions, and Swipe to Archive/Delete.

[60][61][62] Media outlets noticed that the new protection was announced amid a widespread phishing attack on a combination of Gmail and Google's Docs document service that occurred on the same day.

"Smart Reply", a feature originally launched for Google's Inbox by Gmail service, scans a message for information and uses machine intelligence to offer three responses the user can optionally edit and send.

Developed by the Gmail team, but serving as a "completely different type of inbox", the service is made to help users deal with the challenges of an active email.

A travel card contains itinerary details, such as plane tickets and car rentals, and recommends activities, food and drinks, and attractions based on location, time, and interests.

The app now also scans Gmail for bus and train tickets, and allows users to manually input trip reservations.

In the beginning, it was only default on the login page, a reason that Google engineer Ariel Rideout stated was because HTTPS made "your mail slower".

[102] At the end of May 2017, Google announced that it had applied machine learning technology to identify emails with phishing and spam, having a 99.9% detection accuracy.

[116] In October 2007, Google began a process of rewriting parts of the code that Gmail used, which would make the service faster and add new features, such as custom keyboard shortcuts and the ability to bookmark specific messages and email searches.

[122] However, Wired stated that the new change means senders can track the time when an email is first opened, as the initial loading of the images requires the system to make a "callback" to the original server.

Two years later, with 600,000 hits per month, the Internet service provider wanted to charge more, and Gamil posted the message on its site "You may have arrived here by misspelling Gmail.

The company stated that this change was meant to clarify its practices and quell concerns among enterprise G Suite (now Google Workspace) customers who felt an ambiguous distinction between the free consumer and paid professional variants, the latter being advertising-free.

[151] In July 2012, some California residents filed two class action lawsuits against Google and Yahoo!, claiming that they illegally intercept emails sent by individual non-Gmail or non-Yahoo!

[154]A Google spokesperson stated to the media on August 15, 2013, that the corporation takes the privacy and security concerns of Gmail users "very seriously".

[154] Google updated its terms of service for Gmail in April 2014 to create full transparency for its users in regard to the scanning of email content.

Additionally, Google stated that their investigation revealed that "at least" 20 other large companies from a "wide range of businesses" - including the Internet, finance, technology, media and chemical sectors – had been similarly targeted.

In light of the attacks, Google enhanced the security and architecture of its infrastructure, and advised individual users to install anti-virus and anti-spyware on their computers, update their operating systems and web browsers, and be cautious when clicking on Internet links or when sharing personal information in instant messages and emails.

[156][157] The February 2010 launch of Google Buzz, a now defunct social network linked to Gmail, immediately drew criticism for publicly sharing details of users' contacts unless the default settings were changed.