Here are some popular web services that came to Internet in a time period of last three years. All services are orders in year wise descending order.
Wikidata is a collaboratively edited knowledge base operated by the Wikimedia Foundation. Intended to provide a common source of certain data types like birth dates which can be used by Wikimedia projects such as Wikipedia. Just like Wikimedia Commons is for storing media files and makes them accessible for all Wikimedia projects.
Google+ became second largest social networking site on Internet surpassing Twitter in January 2013. It is owned and operated by Google Inc. Google+ has approximately 359 million active netizens.
Duolingo is a free language-learning webb service and crowdsourced text translation platform. It is designed in a way so that, as users progress through the lessons they simultaneously help to translate websites and other documents. As of July 2013, the website offers Spanish, French, German, Portuguese (Brazilian), and Italian courses for English speakers, as well as English (American) for Spanish, French, Portuguese, and Italian speakers.
OnLive is a company which offers a cloud gaming platform and a cloud desktop system. Both are synchronized, rendered, and stored on remote servers and delivered via the Internet.
Diaspora is a free personal web server that implements a distributed social networking service. Installations of the software form nodes (termed “pods”) which make up the distributed Diaspora social network.
Flattr is a Swedish based microdonation provider founded by Peter Sunde and Linus Olsson and launched in March 2010.
Instagram is an online photo-sharing, video-sharing and social networking service that enables its users to take pictures and videos, apply digital filters to them, and share them on a variety of social networking services, such as Facebook, Twitter, Tumblr and Flickr.
Pinterest is a pinboard-style photo-sharing website that allows users to create and manage theme-based image collections such as events, interests, and hobbies. Users can browse other pinboards for images, “re-pin” images to their own pinboards, or “like” photos.