For those of you who are not familiar with Facebook, it is a social media company that enables users to connect with friends within its network and create personal web pages. In fact, Facebook has just beat Google as the most visited website on Earth.

Facebook has announced that it finally achieved positive cash flow in September of 2009, which means that it made enough money to cover the expenses of servicing its 400 million users. On the heels of this good news, people in the industry are sure the company is heading towards an IPO, or initial public offering of stock to the general public -- but no one knows exactly when. If you want to get in on the biggest site out there now, the good news is that many Facebook employees have pre-IPO stock the company, which Facebook began to allow employees to sell in 2009. This has facilitated the creation of a secondary market for Facebook pre-IPO stock. Individuals who are interested in buying Facebook stock before its IPO can gain access to the secondary market by visiting sites such as SecondMarket and SharesPost.

Exchanges like SecondMarket and SharesPost provide investors with a way to buy private shares in attractive startups like Facebook without having to wait for an IPO. They can also help startup workers get needed cash for their shares while they wait for IPOs to happen -- which may never occur. The demand for sites servicing this secondary market has increased because the average time between companies receiving venture funding and "going public" has been steadily increasing.

SecondMarket is a trading platform that specializes in illiquid assets such as bankruptcy claims, CDOs, mortgage-backed securities, etc. In addition, SecondMarket trades in private companies, which allows venture capitalists to sell off their investments before a company goes public. It is important to note that this market is controlled, which means that individuals are required to apply for accreditation before they are able to trade. Despite the fact that buyers and sellers are matched online, transactions must be completed offline. Furthermore, buyers are trading with limited information because private companies do not have the same transparency requirements as public corporations. SecondMarket has announced that it has completed about 40 transactions in the previous year worth roughly $150 million. SharesPost is another trading platform that has emerged to combat the liquidity crisis.

The vast majority of people will not be able to utilize these exchanges because they are only open to a small pool of qualified investors. If you can work with a qualified investors to get in on Facebook's pre-IPO pie through one of these sites, it might be worth it. Yet, the limited number of traders allowed to use these services continues to pose concern for many. Another concern is that it's unclear how much stock has been exchanged through these markets, because the transactions are not public. SecondMarket and SharesPost try to resolve the issue of transparency by offering as much information as possible about the companies they list, but there is not much more they are able or required to do.

On the bright side, if these exchanges manage to flourish, they could help the economy. An investor can free up funds to be invested in other startups by buying shares on a private exchange that can be used to start other companies. Institutional investors can also use these services to expand their holdings to include fast-growing, hot companies like Facebook that have yet to go public and stand to generate a lot of cash. This type of boost can help pension plans and other important, large investment funds that need to continue to thrive for decades in order to help the public at large.

But, you never know. If you do a little homework and find a qualifying investor (or are lucky enough to be one or have access to one), there is every possibility that you can get in on the pre-IPO Facebook game.