If you are creating links for your site then make sure to not follow the paid links. It can lay adverse effect on your site ranking on SERPs. But it sometimes difficult to ensure to identify the paid links. You might have considered that few sites where from you get the option to create the link for your website, clearly show the text $A you have to pay but few of sites haven’t such option.
In order to this issue Google’s spam head Matt Cutts published his video by considering the difficulties of the users to make ensure the fact that will help them to identify such links. Google likely to very concern with this issue and really want to fix it straight way. Google focus for this issue when they found the suspicious links. The question was at the particular site like, who is intended audience, how close is the gift, what is the value of gift, is it an oughtright gift or loan, is the intent of the gift to get links, and would the gift be a surprise to third party.
Below you can see the facts that can help you to ensure and to identify the paid links:
Close To the Value of Money
Explicit Link Sales
Gift Vs. Loan
Intent of Audience
Surprise or Not
Right here you can see the official video published by Matt Cutts