There are a number of quickly growing and expanding companies in the Bay Area. If you're a job seeker, right now is the perfect time to get in on the ground floor. If you're an entrepreneur, consider these companies inspiration and maybe even a hint at where you should start your own business.

1. Prosper

With Steve Vermut as the CEO, this is a peer to peer platform for lending. From 2011 to 2012, it grew in revenue by 532 percent, ensuring it's space solidly as the tenth fastest growing privately owned business in San Francisco. It continues to expand, capitalizing on the crowdfunding trend and helping other small businesses reach new heights.

2. Rocket Fuel

George John is the CEO and co-founder of this media purchasing platform. It grew almost 550 percent last year, and is based in Redwood City. Aptly named, this business is growing fast as a rocket and depends on a programmatic approach to buying media. Letting other businesses serve as the catalyst to make money for you can be a lucrative tactic.

3. Lending Club

Based in the heart of San Francisco, this lending company is just what it sounds like: it provides personal loans. However, with CEO Renaud Laplanche at the helm, it grew 574 percent in a single year and is also banking on the crowdsourcing trend.

4. SpearMC Consulting

This firm has Principal Marcus Bode in charge and offers tech services to other local companies. It enjoyed over 601 percent growth in the past year, but Bode says the move to narrow down the focus to just three services was the biggest growth factor. However, he also says the company lost focus when trying to make money in low-margin Indian/off-shore segments. Lesson learned.

5. Emerge Digital Group

Headed by CEO Chase Norlin, this digital marketing agency experienced a massive 1,488 percent growth in just two years. Norlin credits old fashioned bootstrapping for the spike and a lack of an "exit-focused" approach. He recommends sheer perseverance for entrepreneurs, but as for mistakes? "Too many to list," says Norlin.

6. Back to the Roots

Co-founders Nikhil Arora and Alejandro Velez founded this company in Oakland and have enjoyed almost 846 percent growth in two years. Your grow at home mushroom kits company says partnering up the right way is the key to success. However, a lack of design and quality investment meant their growth was slower than it could have been.

7. Massdrop

Massdrop brings wholesale buying to the consumer with their platform where the community selects which products to purchase as a whole to lower the price of the product.

8. Twilio

As CEO Jeff Lawson keeps moving forward, his biggest accomplishment is the SFO cloud communications business that achieved over 1,185 percent growth in two years.

9. AdRoll

CEO Aaron Bell started the ad software service platform just a few years ago but already has 1,305 percent growth in two years. He credits international expansion and a Facebook partnership as the biggest boost, but says he was too committed to the initial concept which may have held him back.

10. Capstone Technology Resources

The fastest growing SFO company is headed by a woman, CEO Cynthia Reuter. Based in Sausalito, this IT and engineering consulting agency boasts 1,611.2 percent growth in two years. She says connecting with employees, other consultants and clients is key. However, she admits to overlooking the back office demands.