This is included in the Google quality guidelines already: http://www.google.com/support/webmasters/bin/answer.py?answer=35769 . But some are not even aware or just take this for granted, so I'm adding it as a tip.
Beware: nowadays webmasters often receive emails from link building companies requesting you to add their client link to your website for an exchange of a monthly fee. This violates the Google quality guidelines and falls under the paid link scheme, because more often than not these websites are not related to your website's content and you are giving a link to them without editorial merit. Even though they make sense, these companies are requesting you to place these links on your homepage, which is not advisable because it drains out a lot of link juice to your other website pages. Why does participating in these link schemes not help your overall website quality?
1.) These companies force you to remove the rel=nofollow attribute, aside from the fact that the link is sponsored in nature and should be placed with rel=nofollow.
2.) Even though they convince you to make the link look as natural as possible, it can still be classified as a “sponsored link” by analyzing the text that surrounds it - ditto with the targeted page.This is easy to detect, if your website homepage content is talking about “collecting antique widgets”, your reader is expecting the target page of the link to be exactly what your content is talking about. Most citations and links provided with editorial merits are pointed to inner pages of the domain.
The primary reason is that the homepage is rarely used as a reference to details because it’s used in introducing visitors to what the website is all about. But these link building companies are building links to their client's homepage, which of course is not editorial and does not look natural.
Tip #3: Limit Your Advertisements and Speed Up Your Website
It is understandable that every website owner needs to find some way to earn income from their website. But it does not mean that the user experience should be compromised. Some website owners are not aware of this and just decorate their website with a lot of annoying ads that scare users away.
A common measurable aspect is your bounce rate. If your website is ad-heavy and your bounce rate is very high, it indicates that your ads are affecting your user-experience. Some ads are also known to slow down the website and confuse your visitors from distinguishing content from advertisements.
Below are some recommended guidelines:
It is understandable that every website owner needs to find some way to earn income from their website. But it does not mean that the user experience should be compromised. Some website owners are not aware of this and just decorate their website with a lot of annoying ads that scare users away.
A common measurable aspect is your bounce rate. If your website is ad-heavy and your bounce rate is very high, it indicates that your ads are affecting your user-experience. Some ads are also known to slow down the website and confuse your visitors from distinguishing content from advertisements.
Below are some recommended guidelines:
1.) If you are using Google Ad Sense, place the ads in strategic locations so as not to confuse them with website content.
2.) If you are using in-text advertising, consider limiting the number of links to a minimum (for example 3 links per page). Infolinks for example, recommends that you should maximize the number of links to 12 for maximum earnings. But in reality, your website content can look very spammy with a lot of in-text links. Try to wear the user-hat; try reading your website content with this in-text advertising on it. If it disturbs your reading experience - for example you accidentally click on it - maybe it is time to minimize or remove them, as it affects the reading experience.
3.) Optimize your website loading time with ads. Make sure they are loading fast. Remove any pop up banners and welcome banner ads, as they can distract your readers from going directly to the content.
Some useful resources:
Average loading time study: http://www.seochat.com/c/a/Google-Optimization-Help/Average-Page-Load-Time-of-Top-Ranking-Websites-in-Google/
Speed up your website using Page Speed: http://www.devshed.com/c/a/PHP/Speed-up-Web-Page-Loading-Using-Google-Page-Speed/
3.) Remember that every ad added to your site cheapens your site content quality. Limit them.
