how long has Netflix Streaming been like this?

After seeing a few relatives' satisfaction with Netflix Streaming, I recently signed up. I'd heard that Netflix signed a deal for Star Trek TV series (almost all of them) starting later this year, but I assumed that there would be enough to watch until then. Of course, a lot of TV shows have also finished their runs for a few months, so that was another motivator.

After poking around, I have to say I'm amazed. Even pre-Star Trek, Netflix is streaming...

• Farscape
• Doctor Who
• Science documentaries, which are freely available on the PBS websites but not with the same playback possibilities
• Various Joss Whedon signature shows
• Lost 
• Merlin, a fun but simple show that hooked me during its US showing
• Battlestar Galactica (2004)
• Futurama, as if I didn't have all the DVDs
• Heroes, if I ever feel like seeing the latter seasons
• Mythbusters
• Stargate SG-1
• Eureka

I concede that some of these episodes are, er, aged, because I assume that new episodes don't become available on Netflix until long after original airing. Still, especially for the price, this is pretty incredible for someone of my sensibilities...