The title attribute is something you can add to any link. When used correctly the title attribute will on mouseover provide a little more information to the user about the link destination. The text displayed on mouse over is referred to as a “tool tip”.
If your using IE you will see something similar for images. What IE is doing is displaying the “alt attribute”. IE is not all that compliant with W3C standards, and the “alt attribute” should not, and is not displayed on mouseover of images with standard compliant browsers like FireFox.
The “alt attribute” should only be displayed if for some reason the image is not displayed.
On the other hand the “title attribute” should be displayed for any link that is using the “title attribute”. On mouseover you should see a too tip for any site I have linked to from this article.
Personally I have not seen any evidence that using the “title attribute” helps with SE ranking. At this time I do not know of any credible SEO that thinks the “title attribute” is used.
I do think the “title attribute” should be used. Why? Because it will help your visitors. I am slowly adding the attribute to my sites. I try to use it in blog post. In regard to blog articles I could probably provide a better description of the link destination. Even with my quickly written “title attributes” I think they give you a better idea where the link will lead you to.
Regardless of how SEs treat the “title attribute” at this time, they may sart considering it in the future.
If you design web pages to benefit your visitors, it will always help you one way or another. If you only think about SEs what you do may or may not help. Unfortunately some things you do only for SEs could end up hurting your site in the long run.
Use the “title attribute”. Use the attribute as intended. Think of your visitors and not the SEs.