You are using a URL shortening service such as bit.ly, www.snipurl.com, www.budurl.com, www.tinyurl.com, or www.urlborg.com and want to make sure the referrer is being properly tracked.
Most of these services pass the referrer information of the original request through to the final destination. For instance, a shortened URL created by bit.ly and posted in Twitter will still show Twitter as the referrer even though the traffic is coming through bit.ly's service.
We have tested this on bit.ly and tinyurl.com and both cases were successful.
To test any other services you use, you will need an HTTP sniffer such as HTTPWatch or HTTPFox. Create a test URL in the URL shortening service and post it on a Twitter account. Start the HTTP sniffer and click the link. In the information provided by the sniffer, you should see the referrer and be able to verify whether it came from Twitter.com or not.
This will display a pop-up with your referrer. If it says "Referred from:" then there is no referrer to display and Webtrends will not record a referrer for this hit.