When searching on my Wiki, I was unable to search for 'Example' even though the word is used several times in my Wiki (Avlis.shoutwiki.com).
Attempts to search for fragments of the word, such as 'ple', 'exam', 'amp', or 'xamp', also turned up negative.
'Ex', however, worked since that word as a whole is used multiple times in the Wiki.
I was using the "Vector (Default)" skin, and I was able to replicate this on the latest Chrome and Firefox browsers.
I am using Windows 7 64 bit.