If you've got a WD USB hard drive plugged in, it will probably automount both the "content" part and the annoying "WD SmartWare" part.
The SmartWare is WD's attempt to help people out with some backup and other data management software. It cops a fair bit of flack from what I can see. I never used it, so can't comment, but I'm pretty sure it's all Windows-based anyway. On Linux it makes no sense to have it appear all the time.
To get rid of the automount, edit /etc/fstab (requires sudo) and add the following line:
LABEL=WD\x20SmartWare none udf rw,noauto 0 0
Update: While initially I thought the above solution worked, it stopped working at some point, because the "WD SmartWare" has now reappeared on my desktop. So I'm open to any other solutions...