Search engine optimization is hugely important. People can be directed to your site just by typing in a few related terms. It can profoundly affect the amount of traffic you get and can also influence the way people interact with your site.
BUT, while it is possible to design a site that completely caters to the prominent search engines like Google—we mustn't forget that our core objective is to design for people first. The people who need to do things on your site like get information, register, view account balances, or even just get little excited about the features and benefits of your products.
It’s tempting to design for the spiders. To organize information in ways that are optimized so that every bit of information on your site can be picked up by them. There is some middle ground here. You can design for people and BUILD for spiders. Certain compromises can be made in the build process that will help search indexing without dictating the user experience of your site. So get friendly with your developers. They can help ensure that a site design is both customer and search-centric.