Dog pile lets you in on what people are searching for in real time. From an SEO point of view it horrifies me how distant the search terms are from what people clearly mean to be searching for. Thank goodness for search engines giving helpful hints like "Did you mean ____ ?" There are both filtered and unfiltered versions and (fairly obviously) in real time people out there are really searching for x rated pictures. Filtered is a bit more interesting - why do people search for myspace.com???? Or hotmail.com? or youtube.com? If you know the URL why not type it into the big long box designed for URL's at the top of your browser.
On a related note... this guy is RSS feeding his life. Useful? Most likely not. Interesting? Nope!