I covered a very similar question to this recently regarding titles on links, below is a summary of the points, my focus was on accessibility of the title attribute.
1) There is some argument as to how to use the title attribute, especially for images and links. Below are some differing points of view:
Nielsen says: The goal of the link title is to help users predict what will happen if they follow a link.
RNIB proffesional says: Don't use them, except in specific cirumstances.
We said: Title of the page you are linking to, if the text link isn’t already the title of the page.
W3C say: setting the attribute on a link allows user agents (visual and non-visual) to tell users about the nature of the linked resource:
I would recommend having researched further: Whenever you are using a title attrubute think carefully. Writing suitable content should do away with the need for titles. If there is no other alternative then be aware that there is no guarantee the information in the title will be available to your users.
Conclusion - The title attribute is optional on links: So remove it on elements such as buttons. It should be an optional element on content links, if furter information needs to be conveyed (but be aware not everyone will get this info).