David Kutcher: While without any hard evidence, I believe that content that`s not performing and doesn`t serve a purpose has the opposite effect: it can serve to confuse Google`s understanding of your content and your site.
Michael Martinez: Depends on where the content is and how often it`s crawled. "No backlinks" usually isn`t "no backlinks". If nothing else you probably have internal links pointing to the content and they count every bit as much (sometimes more) than external links. Removing old content *MAY* break good crawl pathways, which slows down the re-crawling and re-indexing of a site. It`s just as bad as using "nofollow" attributes on internal links (PageRank sculpting). If the old content existed for a purpose and the purpose is still valid then I would try to improve it, create more visibility for it, and keep it in the mix for as long as possible. The worst thing you can do for SEO is assume something is hurting a site without any evidence to support the assumption. Just because 15 bazillion bloggers say you should remove old content doesn`t mean that`s a good idea. The business decision comes first. The SEO decision must support the business decision. If the boss don`t want the content then get rid of it and make sure the site`s crawl is as tight as possible.
Patrick Healy: If the content serves no purpose - like an announcement for the spring dance of 2010 - I see no reason for it to be there. My rule of thumb is, ask yourself, "does this have any current value?" If yes, then leave it. If no then either rework it so that it does or dump it after putting in a 301 to a page that will fill that purpose.
Jayasanker Jayakrishnan: It`s more with the concept of link dilution. Your total domain or link authority will get distributed across all your existing articles. If an URL attracts no traction, it`s taking away from the whole without contributing. I suggest you try to get traffic before going for the extreme measure.