Entrepreneurial types can't help but envision dollar signs when they think of the immense popularity of social networking sites like Facebook and Twitter. Here are a few ways you can leverage their success into your own.

Develop a Popular Facebook Application
Indian brothers Jayant and Rajat Agarwalla developed the wildly popular Facebook application Scrabulous, which in October, 2007 was bringing in $18,000 a month from advertising, according to the Wall Street Journal, and at its peak was rumored to be bringing in $25,000 a month in ad revenues. While the brothers ended up having some legal difficulties because of copyright issues with the Scrabble board game that resulted in the game being shut down in July 2008, monetizing Facebook applications remains a viable opportunity. Just look at recent success of gaming company Zynga. It's social network applications like Mafia Wars, FarmVille, Texas Hold'em and YoVille had over 60 million active monthly users as of July, 2009. Besides selling advertising, social network applications have raised millions in venture capital and charged users real-world money to purchase virtual goods that enhance the gaming experience.

Use Facebook Marketplace
The application "lets you sell, give away, buy, ask or search for anything you want," according to Facebook. You can also search the marketplace's job listings or advertise your own services as a job seeker. If you're a 501(c)(3) nonprofit, you can list your organization in the Causes section of Marketplace and raise money for your group by selling items or by collecting donations from users who choose to donate the proceeds of their sales to your group. Network for Good, the company that runs the donation program, even sends users receipts for their donations that they can keep with their income tax records. It's free to post a listing on Marketplace, as long as you're a Facebook user.

Tweet With Your Customers
Twitter recommends that its business users think of Twitter as a way to build relationships with customers rather than as a way to simply broadcast advertisements about your company. And it's true - Twitter is an ideal venue for staying on top of what people are saying about your business. It's easier and faster for someone to tweet about your company than it is for them to track down your contact information and get in touch with you directly, so Twitter can give you feedback you'd never hear otherwise. If you pay attention, you can create goodwill for your company by responding to users' tweets, whether it's to resolve a customer complaint or to thank someone for publicly praising your products. You can also offer unique deals via Twitter by providing special coupon codes. If you need more inspiration, Twitter's website has ten case studies of how businesses have used the program to promote themselves.

Build Your Fan Base
If you are your own brand, as is the case for basketball legend Shaquille O'Neal, social networking tools can put you in closer contact with your fans and make you more of a real person to them. Though Shaq was already famous before increasing his online presence through Twitter, over 1.8 million followers know they can get uncensored and amusing insights into what it's like to be Shaq that they might not get otherwise. Some lucky followers even get the chance to interact with him. If you decide to use social networking to promote yourself, make sure to create a separate professional profile to keep your personal life separate from your work life, and keep an eye out for impostors.

Get a Job in Social Networking
If you've got something special, perhaps you can gain a coveted position working for a social networking company. If the prestige isn't enough, consider the perks: Facebook pays 100% of premiums for medical, dental, vision, life insurance and disability, 50% of premiums for dependents, and 50% of monthly gym fees for its full-time employees. It also offers four weeks of paid parental leave, $4,000 in "baby cash," $3,000 a year in daycare assistance, 21 days of paid vacation, unlimited sick days, 11 paid company holidays, free snacks, and a 401(k) plan.

These are just a few examples of how tools like Facebook and Twitter can help you make money. By thinking outside the box and being savvy about the latest technology, you can take advantage of trends in social networking to maximize your profitability.