BTW here's Category5TV
http://www.category5.tv/
The tech shows such as this readily identify that they're using Wirecast.
Wirecast has specific features that draw some shows to even over Tricaster for example.
Encoder that can send to multiple locations with multiple settings and record to hard drive with settings and codecs other than what you're streaming at. This means it might be more commonly used in such shows.
Webcam frame size support. Wirecast detects all the frame sizes a webcam is capable of using. It detects it differently for different models. Category5TV uses is for this reason.
Mac users who need software switching and compositing use it. So sometimes if you find a show says they're streaming from a Mac and using multiple cameras, you can pretty much guess they're using Wirecast. Occupy Wall Street in NYC is using Wirecast for some of their streams or sometimes Livestream Procaster depending on the needs of the the specific coverage they're doing. They're using Macs and Hackintoshes.
Some divisions within the United Nations are using Wirecast. UNICEF have used it for example.
If it looks like a show is using multiple direct camera audio (as opposed to a mixing board), that would be Wirecast because it handles multiple separate audio source inputs. The Pro version has an Audio Inspector which is basically a simple software mixer with faders, channel mutes, sync delay for each hardware audio source input (except DV cameras).
Basically if you know Wirecast specific features you can spot it in use. As you can see from the list many of the shows are not tech shows and they would never have a reason to mention what they're using. You'll find Wirecast used in talk, entertainment, concerts, sporting events.