When building and optimizing a site, it is important to keep the load time to a minimum. While search engines should be able to download your site rather quickly, you want to be sure they are not burdened with trying to download excess that can simply be eliminated. If a spider requires too much effort to read your page it will move on to another site, instead of consuming valuable resources on yours. This same principle can be applied to your user. If the page takes more than a few seconds to download, most users will move one.
This post is part of a continuing series on the topic of:
Optimizing for Maximum Search Engine Performance
Sub-Topic: Search Friendly Elements.