I was interested in knowing percentage of people that use search feature on a website as opposed to the navigation bar. Has search bar become more powerful than the traditional navigation bar for finding data on the site? Has the "sitemap" become obsolete? I know it might be a subjective question but if someone has statistics on this or a white/technical paper, that will be great.
Every site is different. I manage a site that gets over 100k visits a month and we get about 2k searches over the same period of time. The amount of searches done is really a function of how many pages you have in your site, how easy your navigation is, how well you search works, and if you have long tail searches like people checking a government site for a specific law or document from hundreds of thousands.
If you're running an e-commerce site, try having a broken search function sometime and read the feedback. I don't have statistics at hand, but I can tell you that a lot of people use the search as the first attempt at going direct to an item, rather than go through the category navigation, even when the category navigation has the same two click to product result.
The only sitemap I do anymore is sitemap.xml, for large sites a user sitemap is TMI and has to be condensed down to a simple directory which is better set up as a supplemental navigation element anyway so it doesn't get hidden.