There was a panicked discussion thread at Google Webmaster Help forums recently. The person who initiated the discussion wrote:
"Today I found that my entire site has dropped out of site in search results. I have a site that received over 2,000 search visits per day and today that has stopped."
Apparently, he had a bunch of affiliate links on his site. These are links to other sites that he would make money on if someone clicked on the link and bought something on the affiliate site.
Google employee JohnMu jumped into the conversation:
"I browsed your site's reviews a bit and most of the links are either affiliate links or links to the companies without nofollow. This doesn't seem to match your reply regarding the use of nofollow. Perhaps it would be good to double-check and submit a reconsideration request should you find something that could be improved."
With this in mind, it's a good time to refresh your memories on the Google Paid Links policy.
Buying or selling links that pass PageRank violates Google's Webmaster guidelines and can negatively impact a site's ranking in search results.
It appears that the person in this discussion post got in trouble for not adding nofollow attributes to these, what are essentially, paid links.
The primary way to solve this problem is by making these links nofollow. There's a lot of confusion about what this means and how to apply it to your own links. So, let's look closer at the nofollow attribute so we're all clear on the topic.
Nofollow is an HTML code you insert into a link that lets the search engines know that you don't want them to crawl through this link or give it any credit that you were linking to it.
A normal hyperlink looks something like this:
<a href="http://www.example.com/">Anchor Text</a>
That is a standard link and tells the search engines to crawl that link, find the content and, in the case of Google, share some of the PageRank from your page with this new page.
Because Google's algorithm depends on linking, this kind of link has become quite a precious gift. If you link to a site with this kind of standard link, you're telling the search engines, "Here is a page I want to tell you about that is really great. I'm getting nothing from this other than the warm fuzzies that I'm sharing with you and the world a great Web page."
If you link to a page because there is some quid pro quo, then you probably should think about adding nofollow.
It's easy enough. Your hyperlinks would look something like this:
<a rel="nofollow" href="http://www.example.com/">Anchor Text</a>
You probably should link to the page with the nofollow tag if you're getting money, a gift, or to test a product or service.
This also would apply to content that you can't vouch for. Say, for example, you have a blog and you allow commenters to post links in their comments. If you don't know what that content is, you probably should nofollow it (most blog comments are automatically nofollowed, but double-check to be sure).
If you're concerned about losing your Google ranking, take a moment and think about whether you have any links off of your site that you're either getting paid to have or could get paid if a certain action occurs on that site.
Remember, we're talking about linking out to sites that would pay you for the link. We aren't talking about you getting links to your site that you paid someone to give you.
It's interesting that the Google Policy says, "Buying or selling links that pass PageRank." Many people have often thought that they wouldn't get in trouble if they paid for the links pointing to their site. Google's only concern was if someone paid to post a link on your site.
However, if Google could devise a way to determine that a site is intentionally buying links to increase its search engine ranking, they would ding that site. The problem: in Google's policy, they go on to say, "Buying and selling links is a normal part of the economy of the Web when done for advertising purposes."
So, it's a little harder for them to determine if you're just buying advertisement or if you're trying to inflate your search engine rankings. However, if you are buying links to increase your rank, look at your strategy to see if there's any way Google could determine that you're ultimately trying to buy PageRank.
Buyer and seller beware.