For many startups you've never heard of, the founding members are millionaires or even billionaires yet they never make media headlines--and maybe that's just how they want it. Unless you're creating a startup to get famous, it doesn't matter how well-known you are.

There are a number of startups that sound strange, yet rake in the dough. The key is finding a hole in the market and then filling it. Sometimes these disparities are boring or they're just for a B2B clientele, so it's no wonder the general public hasn't heard of them. Here are some of the most successful startups you've never heard of and how they're changing the playing field.

1. Tencent

This Chinese-based company has been dubbed the Facebook of China. Unless you're an avid SM platform junkie, however, you've probably only read about Tencent in passing. Still, it boasts $7 billion in revenues per year with a stunning growth pattern. Those international markets can be highly lucrative.

2. Baidu

Called the Chinese Google, Baidu is by far the No. 1 search engine in China--a country whose sheer population size means that dominating in this market guarantees success. Baidu was founded in 2000 by Robin Li and rakes in about $3.5 billion in revenue each year. It's enjoyed strong and steady growth for nearly 15 years straight.

3. Kaltura

By targeting a number of niches, this open-source platform for video management, distribution, and publishing is putting the competition to shame. More than 300,000 users depend on it, including huge clients like Groupon and Harvard. It just raised $25 million and has no plans to stop. By focusing on niche markets instead of everything, Kaltura has provided a lesson on success for all entrepreneurs.

4. Taboola

This company brings in about $100 million each year but only has a tad more than 100 employees at any given time. In the per capita (or per employee) ratio, it's the highest-grossing company in the world. A content-discovery platform, it offers recommendations for content, utilizing a user's current views. Control is totally in the hands of end users, which is what makes it so successful.

5. Gett

This is a global mobile ridesharing app, but it's still personalized for every local market. Basically, you can get a taxi in 20 major cities around the world. It started in Israel and then went on to enjoy success in Europe and the U.S. Global expansion is Gett's key to success--with more than 1 million clients (including Google as an enterprise client)--and it just raised an extra $42 million to grow even more.

You don't need to be the equivalent of a startup A-lister in order to get rich, love what you do, or be considered a success. Sometimes it's the unsung heroes who really have it made.

Published on: Sep 2, 2014