My post was not meant to introduce confusion but rather give you a sense of what's what.
The easiest way to know is to take your existing adapters, find the brand/model # and look it up online. If you can't find any info on your existing adapters, buy new ones.
As far as buying new adapters, just read the description when you buy it and you'll know whether it's passive or active.
There is no thunderbolt video adapters, just miniDP. Thunderbolt is just a combination of DisplayPort and PCIe and it shares the same connector as the MiniDP. That's why you'll find Thunderbolt to Ethernet/FW800 adapters since it uses PCIe connection but all video connections will be using DisplayPort technology.
Note that the Apple Thunderbolt displays are unique (and proprietary) because they use both technology (PCIe and DP) and won't work with just a DisplayPort cable.
If this is not clear, take a look at these links:
http://www.macworld.com/article/1158145 ... _know.html