How Does Google Determine When It Is A Paid Link

How does Google know when a link is a genuine link, or simply a paid one?  Matt Cutts, the head of Google’s Search Spam has released a detailed video discussing the criteria Google uses to differentiate between the two.

There are five basic criteria uses to see if these links are paid or not.  These five criteria includes:

• Explicit Link Sales
• Close To The Value Of Money
• Gift VS Loan
• Intent of Audience
• Surprise or Not