When referring to URLs in your website decide if you want to use URLs with or without trailing slash (ie. http://www.mavention.com/news/ vs. http://www.mavention.com/news) and use them consistently throughout the whole site.
The same URL with and without the trailing slash are in fact two different URLs for Internet search engines. To optimize for search ranking of your web pages you should choose either format and use it consistently throughout your website. Preferably, the other notation should then return a 301 Permanently Moved header and redirect to the preferred URL.
Internet search engines are not the only reason for which you should use one format for your URLs. When building relative links web browsers differently treat the relative path depending on whether the current URL ends with a slash or not. For example a link such as <a href="my-press-release"> for URL http://www.mavention.com/news/ would result in http://www.mavention.com.com/news/my-press-release. The same hyperlink on the same page opened using a URL without the trailing slash (http://www.mavention.com/news) would point to http://www.mavention.com/my-press-release which is likely to be incorrect.