If you choose to display advertisements on your webpages, this guideline is very important for you to understand. Many websites and webpages have lost their ranking in Google or have been removed from Google entirely because they didn't follow this guideline.
The full text of this Google guideline states "Make reasonable efforts to ensure that advertisements do not affect search engine rankings."
It is fine to display ads on your site, in fact it is the normal way of things on the internet. Displaying ads is not against the Google webmaster
guidelines. What is against the guidelines is to display advertisements which affect ranking.
Your job as a webmaster is to know the difference between advertisements / paidlinks that affect ranking (bad) and those which do not affect ranking (good).
Any advertisement that passes pagerank is against the Google guidelines.
A paid link or advertisment must have a "nofollow" or must be redirected through a file that is excluded by your robots.txt file.
If you do not know what either of those are, we will explain them soon, but first let's cover some common scenarios because most major ad providers already have made their ads appear in such a way that the ads do not affect ranking, but it is your responsibility to ask them if their ads affect rankings. If you don't know, make sure. You are responsible for the things on your webpage.
Yes. Google Adsense ads do not affect ranking. If the only advertising on your webpages is Adsense you do not need to make any changes to your code to make sure you are following this guideline.
Yes. Doubleclick ads do not affect ranking. If the only advertising on your webpages is doubleclick you do not need to make any changes to your code to make sure you are following this guideline.
Yes. Bing ads do not affect ranking. If the only advertising on your webpages is from Bing / Yahoo network you do not need to make any changes to your code to make sure you are following this guideline.
It is only okay if the link you are displaying on your website does not affect ranking and is following this Google guideline.
Affiliate ads are ads, and should not affect page rank. This means that these links must be nofollowed or redirected and blocked by robots.txt, if they are not then you are not following this Google guideline.
If you are paying or receiving money to place links on another website then you are advertising. This means that these links must be nofollowed or redirected and blocked by robots.txt, if they are not then you are not following this Google guideline.
The Google help page which describes how you should deal with paid links states two specific ways to ensure rankings are not affected...
Not familiar with these methods? I will show you what they are.
The quickest and easiest way to make sure a paid link is not passing page rank (affecting rankings) is to use the nofollow tag on the link that goes from your website to the advertiser.
The nofollow attribute tells a search engine spider that the link should not be followed, and that you the webmaster are not personally endorsing the link, you are
just displaying it. It is required that any paid links or advertisements have some sort of notation to this effect.
To add a nofollow attribute to your links is simple, and widely availible to most webmasters. If you can make a link, you can make a nofollowed link too. Here is how you do so.
The links on your webpage look like this...
To add the no follow attribute, we must enter the following code into that link...
The nofollow attribute in the link will then look like this...
Once this is done your link is following this Google guideline. You can check a webpage with our nofollow tool to see which links on a webpage are using nofollow correctly.
For more advanced webmasters, this method requires that you take the advertiser link and send it through a redirect via a page on your website which is blocked by your robots.txt file. This method allows visitors to go through the link but does not pass any pagerank, so it does not affect web rankings.
If you do not follow this guideline you will likely lose your ranking in Google.
Advertisements are sometimes also known as "paid links" because someone is paying you (the website owner) to place a link on your page that points to another page. That link might be an image ad or a text ad, but it will virtually always be something on your page that links to another page. These links that someone bought were not put there for editorial or natural reasons, they were put there because someone paid for it.
Google and other search engines use links as one of the important ways they rank webpages, but paid links were starting to mess things up because there was no way
for search engines to determine whether a link was a natural link, put there to benefit users - or a paid link, put there to advertise a product for a fee.
Many people took advantage of this and thought...
"Hey! I can pay a whole bunch of people to link to my site and then it will rank well in Google because it will have so many links to it!"
These people then started buying ads and links on webpages like yours. In doing so they were manipulating Google to make their site rank higher or seem more important than it really was by buying paid links. Their motivation was not attracting users to their pages, it was to get more links to make their own web site rank higher.
It is of course against the Google guidelines to manipulate or "trick" Google, and it is also against the guidelines to be in "link schemes".
Several years ago this method of paid links worked well for rankings but as Google became more adept at finding these links, the advertisers and the website owners displaying these links or ads were punished by losing their ranking or being removed entirely from the Google index.
Google spent alot of time and effort to let people know that buying links was a deceptive practice that could get you banned from Google.
*not affiliated with Google Inc