Trading OTC markets

Over the counter (OTC)
In general, the reason for which a stock is traded over-the-counter (OTC) is usually because the company is small, making it unable to meet exchange listing requirements. Also known as "unlisted stock", these securities are traded by broker-dealers who negotiate directly with one another over computer networks and by phone.

As such, OTC stocks are generally unlisted stocks which trade on the Over the Counter Bulletin Board (OTCBB) or on the pink sheets. Be very wary of some OTC stocks, however; the OTCBB stocks are either penny stocks or are offered by companies with bad credit records.
Source: http://www.investopedia.com/terms/o/otc.asp

My Opinions
Hmm..means even small businesses can be listed and raised funds in this markets. But its very high risk. Reason?

What i observed, from trading OTC, you wont be able to know the buying and selling price in queue for this market unlike equity markets such as NYSE or SGX, where brokeages offered services to see the queuing volumes and prices offered.

You may be queuing to buy at 0.05c for that counter, and the order may not be filled even if the platform shows that your price has been penetrated.

To know if the stock is a OTC counter, normally they have a stock symbol will end with a .PK or . OB, depending where it is traded, i guess...haha..will need to confirm this detail.

Risks of OTC
Although stocks quoted on the OTCBB must comply with SEC reporting requirements, other OTC stocks, such as those stocks categorized as Pink Sheets securities, have no reporting requirements, while those stocks categorized as OTCQX have met alternative disclosure guidelines through Pink OTC Markets.

The OTC market presents investment opportunities for informed investors, but also has a high degree of risk. Many OTC issuers are small companies with limited operating histories or are economically distressed
Source: http://en.wikipedia.org/wiki/Over-the-counter_(finance)

Readings on FAQ on OTC Mtk trading:
http://www.pinksheets.com/pink/faq.jsp#investor