Zillow serves the full lifecycle of owning and living in a home -> buying, selling, renting, financing, remodeling and more

Zazzle is an online retailer where users can sell their own self-designed merchandise or buy merchandise from other users. Typical items include t-shirts and posters

YouTube is a video-sharing website where users can upload and watch videos, subscribe to user channels and leave comments

Yelp publishes crowd-sourced reviews about local businesses

XING is a European career-oriented social networking site

Xanga is a website that hosts weblogs, photoblogs, and social networking profiles

WordPress is an open-sourced blog platform which provides users with templates to utilize for on or offsite blogging

Weibo is Chinese microblogging website

Vimeo is a video-sharing website where users can upload and watch largely high-quality, HD videos and subscribe to user channels

Veoh is an Internet television website specializing in network television and movie content, along with independent productions and user-generated videos

Ustream is a provider of cloud-based, end-to-end video solutions for media and enterprises

Urbanspoon was a restaurant information and recommendation service

TypePad is a blogging service that shares technology with Movable Type and is used by both tech-savvy and non-technical users

Twitter is an internet service where users can update the world in real-time as to their current activities, thoughts and location in 140 characters or less

Tumblr is a blogging platform geared towards 'hip,' urban youth. Posts are generally short, and might include videos, quotations, pictures and links

TripIt organizes travel plans and allows users to share them

TripAdvisor is the web's largest travel review website, which allows users to make travel plans (i.e. book flights/hotels) and write reviews of hotels, restaurants etc

Topix is an online community where users can comment on aggregated news articles and discuss local and national events with each other

Tinder is a location-based social search mobile app that allows users to like or dislike other users, and allows users to chat if both parties swiped to the right

ThisNext is a community of shoppers that share new and unique products and trends with the public

The online service imeem was a social media web site where users interacted with each other by streaming, uploading and sharing music and music videos

Tagged is a social network where users can make profiles, post pictures, chat and play games with friends and send virtual gifts

StumbleUpon is a 'discovery engine,' which recommends random websites, videos, photos etc. based on user taste and preferences

SourceForge acts as a management system for software developers to regulate open source software development and projects

SoundCloud is a platform that puts your sound at the heart of communities, websites and even apps. Watch conversations, connections and social experiences happen, with your sound as the spark

Smugmug is a premium photo sharing site primarily used by professional photographers

SlideShare is a slide hosting service where users can upload files privately or publicly. The site is considered to be similar to YouTube, but for slideshows

Skype is a telecommunications software that provides video chat and voice calls over the Internet

Shelfari was a social cataloging website for books that got merged with GoodReads

Scribd is a digital library, e-book and audiobook subscription service that includes one million titles

ReverbNation helps Artists grow by introducing them to music industry partners and exposing them to fans

Reddit is a social news website where the registered users submit content, in the form of either a link or a text post

Quora is a question-and-answer site where questions are asked, answered, edited, and organized by its community of users

Polyvore is a community-powered social commerce website. The company's virtual mood board function allows community members to add products into a shared product index, and use them to create image collages called 'Sets'

PlentyOfFish is an online dating site where singles can take personality tests and find compatible mates

Pinterest is an online pinboard. Organize and share things you love

Pinboard is a social bookmarking website

PictureTrail is a photo-sharing site which allows users to host images and share photos via a user profiles

Picasa is an image-organizing, photo-sharing site developed by Google where users can upload and edit digital photos

PhotoBucket is a photo-sharing service which allows users 500MB of free space where they can host, share (i.e. on MySpace), or keep their photos private

Pandora is an internet radio station created by the 'Music Genome Project,' which automatically recommends and plays music based on user's listening preferences

On Gravatar, users can register an account based on their email address, and upload an avatar to be associated with the account

OKCupid is a free online dating network where singles can message, share blogs and photos and find compatible users through member-created quizzes

Netlog was a social networking site with features like chat, search, photos and games

MyYearbook was a social networking site which was acquired by MeetMe, a social networking site with features like chat, meet, discuss, and live video

Myspace is a social networking website offering an interactive, user-submitted network of friends, personal profiles, blogs, groups, photos, music, and videos

Mixi is an online Japanese social networking service

Metacafe is a video-sharing network where users upload, discuss, review entertaining short-form (90 seconds on average) clips

Menuism is a service for foodies and food lovers that offers restaurant reviews, individual dish reviews, restaurant menus and locations, and a social networking feature

MeetMe is a social networking site with features like chat, meet, discuss, and live video

Match.com is a popular online dating network which allows users to create profiles and meet like-minded singles looking for love

Lyrics.com is a searchable online database of song lyrics where users can share favorite songs, create profiles and make customizable playlists

LiveJournal is a blogging platform/social network where users keep a blog or journal, comment on friends' blogs and join virtual communities

LinkedIn is the world's largest professional network with 300 million members in over 200 countries and territories around the globe

Last.fm is a music website, founded in the United Kingdom in 2002. Users can play music online, find out more about their favorite artists, and get music recommendations

Lanyrd is a conference directory website

Kongregate is an online gaming site where users can upload and play flash-based games, earn points and rewards for high scores and discuss in user forums

Klout is a website and mobile app that uses social media analytics to rate its users according to online social influence via the 'Klout Score'

Jango is a free online music streaming service that allows users to create and share custom radio stations

Instagram is a free photo sharing app which allows users to take a photo, apply a digital filter to it, and then share it on multiple social networking services

IMVU is a social game and entertainment site where millions of people meet, chat , play games and have fun

ImageShack is a subscription-based image hosting website

IGN is an entertainment website that focuses on video games, films, music and other media

identi.ca is a free and open source social networking and micro-blogging service

Hyves was a social networking site in the Netherlands

Hulu is an American subscription video on demand service

Hi5 is a social networking site where users can create a profile to showcase their interests. Users can upload pictures, play games, and more

Hacker News is a social news website focusing on computer science and entrepreneurship

Google+ aims to make sharing on the web more like sharing in real life

Google Buzz was a social networking, microblogging and messaging tool that was developed by Google and integrated into their web-based email program, Gmail

Goodreads is a site to help people find and share books they love

GitHub is a Git hosting site that helps users manage software development projects. It also offers free public repositories, issue tracking, code review and more

Get Satisfaction is a customer community software platform for technical support

FriendFeed was a real-time feed aggregator that consolidated updates from social media and social

Foursquare is a location-based social networking site where users can 'check-in' at vicinities with mobile devices

Fotolog is a photoblog website where users share pictures through online photo diaries or photo blogs

Flixster is a go-to mobile destination for discovering movies

Flickr is an image and video hosting website where users and bloggers share, embed, and host photographs and images

Facebook is a social network where users can create a profile, add friends, exchange messages, and join common interest user groups

Eventful aims to help users search for, track, and share information about events. Users can also create calendars through the service

Etsy is an ecommerce website which focuses on the selling of handmade and vintage items, and arts and crafts supplies

eBay is an online auction and shopping website in which people and businesses buy and sell a wide variety of goods and services worldwide.

Disqus is an online service which allows users to create a profile for organizing and following their comments across hundreds of websites

Diigo is a social bookmarking website that allows signed-up users to bookmark and tag Web pages

deviantART is an online community showcasing varied forms of user-made artwork and aims to provide a place for any artist to exhibit and discuss works

Delicious is a social bookmarking service for saving, organizing and sharing personal bookmarks. It is also used to discover the newest and most popular bookmarks

DailyMotion is a video sharing service website where users can find or upload videos about their interests

Crunchbase is a community site where users can discover industry trends, investments, and news about global companies

CNN IReport accepts video, photos and audio from a computer or cell phone. A compilation of news items submitted by citizen journalism

Citysearch is an online city guide that provides information about U.S. businesses in the areas of dining, entertainment, retail, travel, and professional services

Care2 is a social network website that was founded in 1998 to help connect activists from around the world

CafeMom is a community where moms come together to get advice and support on topics like pregnancy, health, fashion, food, entertainment, and more

Break is a humor website targeted to males aged 18-35 that features comedy videos and flash games

Blogger is a blog publishing service with many features including geo-tagging and time-stamped entries for private or multi-user blogs

Blip.fm is a social internet radio where users share music

BlackPlanet is a social networking site targeted to the African American community with music, jobs, forums, chat, photos, dating personals and groups

Behance is an online portfolio site for creative professionals across multiple industries including photography, graphic design, illustration, and fashion

Bandcamp is an online music company that allows fans to buy music directly from the artists

Ask.fm is a Latvia-based social networking website where users can ask other users questions, with the option of anonymity