In this part I'll try to cover link usability and accidental clicks on Ads.
Some webdesigners tend to rely heavily on accidental clicks. They layout their pages in a bad way, with poor contrast to increase the CTR for their Ads. This will again harm the advertisers, since they will be paying for such worthless clicks.
Usually this means people who click an Ad by accident, thinking it was part of the site, either because it was placed to close to navigation links, or other clickable content, or simply because the site was designed with such poor contrast, that the user got confused. There are no valid reason why Webdesigners should get payed for these clicks.
Note. Its better to simply layout your pages right in the first place, to avoid as many of these Accidental Clicks as possible.
A whole lot of webdesigners, seam to neglect the importance of having visited links apear in a different color, some even remove the difference on purpose, to increase the accidental click through rate.
Visited links and Unvisited links
Some webdesigners remove the difference between visited and unvisited links, this is a very bad idea, since it will be harder for your visitors to keep track of the links they already visited.
Note. Depending on your layout, and how many links you got, this feature actually helps your users to navigate your site.
Generally its a bad idea to disable it. The styles and colors of your links, should hold a suitable contrast to make sure users find it easy to navigate on your site.
Hover effects on Links
Do not neglect the importance of hover effects, this is almost todays answer to underlined and blue links.
Wait, dose this mean that links shouldn't be Blue and Underlined?
Links dosn't nessesarily need to be blue and underlined, its an outdated understanding of usability. With todays modern CSS layouts, its actually recommended to be more creative and thoughtful with your links, both for usability reasons, and for design reasons.
Note. It however might be a good idea to keep them Underlined, so that you don't rely on color alone
And this is only for the sake of user friendliness. Keep in mind that some users may not be able to view these colors the same way as people with normal eyesight.
Be creative with your links, applying a simple hover effect will help your users to navigate your site, by better indicating a link. The majority of users are still registrering underlined text as links, the color however dosn't matter much anymore. So we have 2 good reasons to underline links, 1:) The majority is used to seeing links as underlined. 2:) Its a bad idea to rely on color alone to indicate clickable content.
Its fine to remove the underline on links in navigation menus, and places where its obvious that its a link. But links occurring in the content should be underlined in most cases. This will help users to register a given link, hover effects will help your users in this process, and it adds another level to your layout by making it more graphically appealing.
Sessions vs URL Parameters
Sometimes its better to use URL Parameters, instead of sessions.
One case would be when publishing RSS feeds for Articles on your site dynamically. It might seam like an easy solution to store the number of the Article/Post in a session variable, but this would break your application if your users have cookies turned off in their browser. And it will make crawling the pages harder for search engines, since they might chose to access the feed directly instead of visiting the main article first, or they might not even accept cookies.
These are things to keep in mind about links, the next Article on Usability will cover some basic aspects of layout and contrast.