Microsoft officially unveiled the new operating system, Windows Phone 7 Series, at the Mobile World Congress in Barcelona on February 15, 2010,[3] and revealed additional details at MIX 2010 on March 15, 2010.

[5] As its original name was criticized for being too complex and "wordy", the name of the operating system was officially shortened to just Windows Phone 7 on April 2, 2010.

[7] Upon the release of Windows Phone 7's "Mango" revision, additional manufacturers became partners, including Acer, Fujitsu, and ZTE.

Support for additional languages and regions were subsequently brought through both the Mango and Tango updates to the OS respectively.

Windows Phone 7 features a user interface based on a design system codenamed and commonly referred to as Metro.

[13] For example, the Pictures hub shows photos captured with the device's camera and the user's Facebook photo albums, and the People hub shows contacts aggregated from multiple sources including Windows Live, Facebook, and Gmail.

[13] The default Windows Phone user interface has a dark theme that prolongs battery life on OLED screens as fully black pixels do not emit light.

[17] Users input text by using an on-screen virtual keyboard, which has a dedicated key for inserting emoticons,[18] and features spell checking[18] and word prediction.

This allows a conversation with a person to be held through multiple platforms (such as Windows Live Messenger, Facebook messaging, or SMS) within a single thread, dynamically switching between services depending on availability.

Here, information from each of the contacts is combined into a single page which can be accessed directly from the Hub or pinned to the Start screen.

[18] This hub integrates with many other apps that provide video and music services, including, but not limited to, iHeartRadio, YouTube, and Vevo.

The video file formats supported include WMV, AVI, MP4/M4V, 3GP/3G2, and MOV (QuickTime) standards.

[27][28] Unlike the previous Windows Mobile operating system, there are currently no third-party applications for handling other video formats.

The image file formats that are supported include JPG/JPEG, PNG, GIF, TIF and Bitmap (BMP).

The Games hub provides access to games on a phone along with Xbox Live functionality, including the ability for a user to interact with their avatar, view and edit their profile, see their achievements and view leaderboards, and send messages to friends on Xbox Live.

[33] Windows Phone also has a voice recognition function, powered by TellMe, which allows the user to perform a Bing search, call contacts or launch applications simply by speaking.

Windows Phone 7 features a card-based task switcher which can be accessed by pressing and holding the back button.

As of the "Tango" update, the requirements were revised to allow for chipsets with slower processors, and for devices to have a minimum of 256 MB of RAM.

Certain features of the operating system, and the ability to install certain resource-intensive apps are disabled on Windows Phone devices with under 512 MB of RAM.

[78] What Engadget and Gizmodo felt were notable omissions in a modern smartphone OS[citation needed] have largely been addressed in the Mango update.

[citation needed] ZDNet praised the OS's virtual keyboard and noted the excellent touch precision as well as powerful auto-correct and revision software.

[18][79] The touch responsiveness of the OS has also been universally praised by all three sites with reviewers noting the smoothness of scrolling and gestures like pinch to zoom in web browsing.

[80] Engadget and ZDNet applauded the integration of Facebook into the People Hub as well as other built-in capabilities, such as Windows Live, etc.

Windows Phone 7 was presented with a total of three awards at the 2011 International Design Excellence Awards, voted by an independent jury[82] at an event co-sponsored by Microsoft, among others;[83] Gold in Interactive Product Experience, Silver in Research and Bronze in the Design Strategy.