There are actually some legitimate uses for shortening services.
The examples in my answer herehere would not have been possible without a shortening service. SO was misinterpreting the URL because it contained a regular expression as part of the query string:
http://www.strfriend.com/vis?re=<([A-Z][A-Z0-9]*)\b[^>]*>(.*%3F)</\1 However in the answer I explicitly stated the reason for the shortened URLs.