After a much-mentioned article by Jakob Nielsen, “mega menus” became all the rage, but there are some serious issues to consider before diving in. The can create serious usability issues and negatively impact your site information architecture and, ultimately how you are found, ranked and categorized by the search engines.
Usability Advantages and Disadvantages of Mega Menus (Mega Menus Part 1)
,Mega Menus and SEO Concerns and Solutions (Mega Menus Part 2)
,Search engines have made a lot of progress in terms of figuring out what your page is about, but large numbers of navigation links muddy the signal you send to the search engines, both about your page and about the rest of your site. There are lots of possible solutions, but the real solution is getting the information architecture right.