I'm redesigning a e-commerce website that uses a global browse/search mechanism in the form of an alphabet megadropdown. There are a LOT of different brands and products, so the intent of the alphabet is clearly to make browsing/searching simpler. However, I'm wondering if there is a better way to implement something like this in a way that provides a better user experience.
Another approach to this is something like Newegg (http://www.newegg.com/ProductSort/BrandList.aspx?Depa=0&name=All-Brands) does, which is a single button that redirects a user to basically a sitemap. However, my concern with the approach is that the amount of SEO keywords on the home page would probably take a hit, and requiring the user to head to another page might be a little too much.
Any suggestions for how to approach this? Either a nice/clean way to incorporate the alphabet, or some benefits to doing something like the newegg approach?