Venture capitalists and investors are continuing to pour money into startups.
These companies range from familiar firms like Pinterest and Uber, to more-recent billion-dollar startups like messaging app Tango and events platform Eventbrite.
Note: This slideshow only includes companies that are privately held, have raised money in the last three years and have at least one venture capital firm as an investor.
Evernote first entered the billion-dollar club in May 2012 when it raised a $US70 million D round. At the time, the company was valued at $US1 billion.
To date, Evernote has raised over $US240 million from Allen & Co., China Broadband Capital Partners, DoCoMo Capital, Harbor Pacific Capital, m8 Capital, Meritech Capital Partners, m8 Capital, Morgenthaler Ventures, Sequoia Capital, T. Rowe Price, and Valiant Capital Partners.
Event ticketing platform Eventbrite is one of the newest members of the billion-dollar club. Earlier this month, Eventbrite raised $US60 million at a $US1 billion valuation.
Founded in 2006, Eventbrite has raised $US197 million to date.
Dianping, China's largest restaurant review site, has raised $US164 million to date.
Last year, Dianping reportedly turned down a buyout offer from Google China. Tencent made an undisclosed investment in Dianping earlier this year, with a rumoured valuation of anywhere between $US1.8 billion and $US2 billion.
Known for its headphones and now its music-streaming service, Beats Electronics is the brainchild of rapper Dr. Dre and producer Jimmy Iovine.
Beats Electronics has raised $US560 million to date, and is currently valued at $US1 billion.
Xunlei Network Technologies, backed in part by Google, is one of the largest peer-to-peer file-sharing services.
Founded in 2003, Xunlei has raised $US111 million to date and is worth $US1 billion.
Investors: Ceyuan Ventures, Fidelity Growth Partners Asia, Google, IDG Capital Partners, Morningside Group, Primavera Capital Group, RW Investments.
Mobile security company Good Technology helps protect data on employees' personal devices.
Good Technology has evolved into a full mobile computing service to enterprise companies with its acquisition of BoxTone. Following a $US50 million round in April, Good Technology is now worth $US1 billion.
The security company has raised $US396 million since its founding in 1996.
Coupons.com recently filed for an IPO so expect that valuation to go up. The company lets users find and print coupons before they go out shopping. This simple concept caused Coupons.com to make $US115 million during the first nine months of 2013.
CloudFare, which protects websites from online threats, is worth $US1 billion following a $US50 million round closed in December 2012.
Founded in 2009, CloudFare has raised $US72 million to date from investors including Greenspring Associates, New Enterprise Associates, Pelion Venture Partners, Union Square Ventures, and Venrock.
Following a recent $US250 million round led by Alibaba, messaging app Tango is now worth $US1.1 billion.
Tango is a free messaging service, similar to hot apps like WhatsApp and Viber, which were both recently acquired for billions of dollars.
Founded in 2009, Tango has raised $US367 million to date.
The flash sales site raised an additional $US138 million in 2011 at a $US1.1 billion valuation.
Last November, there was a bunch of chatter regarding a potential IPO for Gilt Groupe. It's reportedly eying to go public later this year.
Back in June 2013, design startup Fab raised $US150 million in part one of its Series D round at a pre-money valuation of $US1 billion.
To date, Fab has raised a whopping $US335 million from investors including Andreessen Horowitz, Atomico, Baroda Ventures, Docomo Capital, First Round Capital, German Startups Group Berlin, ITOCHU, Mayfield Fund, Menlo Ventures, Phenomen Ventures, Pinnacle Ventures, RTP Ventures, ru-Net Ventures, SingTel Innov8, SoftTech VC, Tencent Holdings, VTB Capital, Washington Post, Zelkova Ventures, A-Grade Investments and SV Angel.
MongoDB makes the wildly popular database that customers like eBay, MetLife and The New York Times use to organise their documents and files.
After raising a huge $US150 million round last October, MongoDB became a $US1.2 billion company. To date, MongoDB has raised $US231 million.
It seems as if its next stop will be an IPO.
Sogou is a search engine that can find text, images, music and maps. According to CrunchBase, people in China have searched over 10 billion pages and has a daily update of 500 million pages. One cool aspect of the service is that it can identify malicious software on websites and provide users with the cleanest results on search pages.
Deem, the enterprise startup that provides travel and expense software to companies like Coca-Cola, Goldman Sachs and Siemens, has raised $US424 million to date.
That values the company at $US1.4 billion.
Fanatics Inc. sells official licensed jerseys and other memorabilia for sports fans to buy. Sports apparel is a lucrative market, and Fanatics Inc. should grow even more in the new year.
Fanatics has had a rumoured valuation of up to $US3 billion, but Venture Source has only confirmed a $US1.5 billion valuation.
Founded by brothers Patrick and John Collison, Stripe -- a payments startup that creates an easy way to accept payments on the Internet -- is now seen as a threat to PayPal.
Just last month, Stripe raised $US80 million at a $US1.8 billion valuation, making the startup one of the newest additions to the billion-dollar club.
Snapchat, the disappearing messaging app that rejected a buyout offer from Facebook, is worth $US2 billion. To date, Snapchat has raised $US130 million.
Nicholas Woodman and GoPro have come a long way since the camera startup's inception in 2002. More than a decade later, GoPro is gearing up to go public.
Last year, GoPro made nearly $US1 billion in sales. In 2012, GoPro made $US521 million in sales with a valuation of $US2.3 billion.
GoPro is expected to publicly file its initial public offering in May or June.
Airbnb closed a $US200 million round of financing in 2012, bringing its total funding to $US526 million.
Airbnb was previously valued at $US2.5 billion; it first joined the $US1 billion valuation club when it raised $US112 million in 2011.
The latest rumour is that Airbnb is raising another round at a whopping $US10 billion valuation, which would value it more than Hyatt hotels.
Bloom Energy creates fuel cells called Bloom Boxes that produce clean energy. The first customers for these devices included Walmart, Federal Express and Coca-Cola, according to The Guardian. The cost of these boxes are $US750,000, but they hope to cut that down $US3,000 within a decade.
That may be sooner rather than later. In order to cut down on greenhouse gas emissions, Fast Company writes, eBay purchased five boxes and saved $US100,000 in under a year.
Legendary Entertainment is a production company that achieved considerable success co-financing and co-producing the 'Dark Knight' trilogy with Warner Bros. studios. It's one of the first companies to partner film production with hedge fund investors. While Legendary's partnership with Warner Bros. was lucrative, that deal expired in 2013. Universal Studios will be Legendary's new home in 2014.
Founded in 2005, Beijing-based VANCL is expanding to sell a variety of high-end brands.
To date, VANCL has raised $US472 million, touting a valuation of $US3 billion.
Jack Dorsey's mobile payment solution, Square, is another billion-dollar startup, and is now valued at $US3.3 billion.
In 2012, Square raised a $US200 million Series D round with participation from Citi Ventures, Rizvi Traverse Management, and Starbucks. To date, Square has raised $US345 million from Citi Ventures, Khosla Ventures, Kleiner Perkins Caufield & Byers, Rizvi Traverse Management, Sequoia Capital, Starbucks, and Tiger Global Management.
Originally, Jawbones were intended as noise-cancelling headphones for the military. Now, these wireless speakers and Bluetooth headsets that sync with mobile devices are used by music lovers and exercise enthusiasts all over the world.
Pinterest joined the billion-dollar valuation club after a $US100 million investment led by Rakuten in May 2012. Following a $US225 million funding round in October 2013, Pinterest's valuation jumped up from $US1.5 billion to $US3.8 billion.
Zalando is an online retailer that sells clothing and other fashion products for 14 different countries in Europe. Originally, CEO Robert Gentz was inspired by Zappos and created the site to sell a luxury line of shoes before he expanded it. Subscribers receive magazines that include special holiday sales, which has helped Zalando become the king of e-commerce overseas.
4. Jingdong, formerly known as 360Buy, is one of China's largest online retailers by transaction value.
Described as the Amazon of China, Jingdong is the largest online retailer in China. Founded in 2004, the company has raised $US2.2 billion to date, valuing the company at $US7.3 billion.
Cloud storage startup Dropbox, which has more than 200 million users, was valued at $US10 billion as of December 2013.
To date, Dropbox has raised $US507 million from Accel Partners, Benchmark Capital, BlackRock Private Equity Partners, Glynn Capital Management, Goldman Sachs Group, Greylock Ventures, Index Ventures, Institutional Venture Partners, RIT Capital Partners, Sequoia Capital, Valiant Capital Partners, and Y Combinator.
Xiaomi is a technology company that creates and produces smartphones, apps and other consumer electronics. The company's low-price smartphones have been a big hit in China: it sold 18.7 million smartphones last year, which makes it a serious threat to Apple in a lucrative market. Former Android exec Hugo Barra is helping Xiaomi with an international expansion, so this company has big plans ahead.