Webtrends Analytics 9 Adminstration Guide, November 2012
Search engines encoded differently than your website may refer visitors to your site. A profile specifies the language and encoding of the website activity it tracks. When search phrase data encoding does not match the language and encoding specified in the profile, Webtrends cannot display it properly in reports.
For example, you specify Japanese as the language for a profile, which Webtrends analyzes using the Shift-JIS character set. Visitors come to your site from search engines that encode search phrases using a different Japanese character set, and Webtrends cannot recognize the characters that make up their search phrases. It displays squares in search engine reports rather than text. You can use the string encoding plug-in to convert search phrases to the encoding specified in the profile.