Yahoo, Inc. (NASDAQ: YHOO) is a computer software and Web search engine founded in 1995. The company is headquartered in Sunnyvale, California, and it is one of the most visited websites on the Internet, with a reported 130 million unique users per month. Yahoo receives an average of 3.4 billion page views per day.

With the massive success of the company and its ability to generate working capital, it has adopted a strategy of adding to its growth through the acquisition of companies. Yahoo's first acquisition was the purchase of a search engine called Net Controls in 1997; as of 2015, the company has acquired a total of 114 companies.

1. Broadcast.com

Broadcast.com was an Internet radio company founded in 1995 by Christopher Jaeb, Todd Wagner and Mark Cuban. The company was one of the first companies to broadcast live radio on the Internet, providing sports broadcasts, presidential debates and other events.

The company set what was at that time the one-day record for initial public offerings (IPOs) by increasing its share price by almost 250%. In April 1999, Yahoo acquired the company for $5.7 billion in stock and split it into separate services: Yahoo LAUNCHcast for music streaming and Yahoo Platinum for video entertainment.

Yahoo now offers Yahoo Platinum's technology in two new services: Yahoo High Speed Internet and Yahoo Plus. Yahoo LAUNCHcast has been renamed Yahoo Music Radio, and it is the company's music presence on the Web.

2. Overture Services

Overture Services, formerly GoTo.com, was one of the first companies to offer a pay-per-click search service. With this service, advertisers could bid on how much they wanted to pay to appear at the top of search results in response to specific keywords. An advertiser paid the company every time a user clicked on an advertised search link to its website.

Yahoo, Overture Services' highest-paying customer, acquired the company in 2003 for $1.63 billion. This was a huge acquisition for Yahoo, since it allowed the company to monetize its search function. Since the acquisition, the company was renamed Yahoo Search Marketing. It was the first time Yahoo offered a successful pay-for-placement service.

3. Tumblr

Tumblr is a microblogging service and social networking website founded by David Karp. The platform lets users post multimedia and other forms of content in the form of short blog posts. Users can follow other blogs as well as maintain their own. Tumblr hosts over 252 million blogs, and it is headquartered in New York City.

The company has been able to realize incredible growth since its inception in 2007, when the service gained 75,000 users in its first two weeks. Since then, Tumblr has had exponential growth in terms of bloggers and followers. In May 2013, Yahoo announced that it had reached an agreement to acquire Tumblr for $1.1 billion in a cash-only acquisition. Karp has remained as CEO, and the deal allowed Yahoo to increase its social presence through one of the biggest social media and blogging platforms in the world.

4. BrightRoll

BrightRoll is a programmatic video advertising platform that was founded in 2006. The company is headquartered in San Francisco, California, and it has offices throughout the world. The BrightRoll platform is the top delivery system for digital video ads, and it manages and measures ad campaigns across Web, mobile and television.

According to comScore, BrightRoll is the leader in reaching the highest numbers of unique users in the United States and is ranked among the top companies in video ads served. The platform provides a real-time marketplace for brands, agencies, agency trading desks, demand-side platforms and ad networks to connect with digital audiences through video ads.

Yahoo purchased BrightRoll in 2014 for $640 million. This gives Yahoo one of the best ways to monetize its online content.