TBBT makes fun of being a nerd (or a geek) at the expense of nerds and geeks. The audience is never the nerd or geek themself; it's everyone else. TBBT does not intend for you to emphathise with the nerds, they are there for your enjoyment. Essentially, TBBT makes nerds into the new samba blacks.
There is nothing smart about the jokes; the punchline (and frequently, the entire joke) is usually [something vaguely nerdy sounding that most people don't know]. Basically, TBBT just randomly says "quantom superstring theory" and you are expected to laugh at it because the phrase sounds ridiculous; there usually isn't any more context to it than the utterance of the nerdy-sounding thing.
In contrast, Community takes the concept and builds into something substantial. They'll take "quantum superstring theory" and, for example, turn it into an episode where the vibrations of silly string perfectly predict events going on elsewhere on campus.
BBT has a UCLA processor on staff as a fact-checker who fills in the realistic science parts: http://en.wikipedia.org/wiki/David_Saltzberg -- when interviewed he said his fellow scientists were at first wary of the show but then wildly enthusiastic after actually seeing the first season.
Mayiam Bialik (a minor but recurring character) holds a PhD in neuroscience (taken after playing Blossom so many years ago) and there's been quite a show of renowned scientists as guest stars (at last two Nobel prize recipients, Hawkings and George Smoot). I think they'd disagree with with your dismissal of the scientists portrayed as "new samba blacks".
On the 5-season Bluray set they show how the show is taped -- I think it took 4 hours to get the 25ish minutes done, all in front of a live studio audience, and an incredibly engaged one. In the breaks the interview some of the audience -- one was a female rocket scientist from Texas.
I personally found "Community" rather dull, and far less engaging than other in the new wave of non-laughtrack comedies/mockumentaries a la CYE, Modern Family, Veep, Parks & Recreation and Arrested Development.
There is nothing smart about the jokes; the punchline (and frequently, the entire joke) is usually [something vaguely nerdy sounding that most people don't know]. Basically, TBBT just randomly says "quantom superstring theory" and you are expected to laugh at it because the phrase sounds ridiculous; there usually isn't any more context to it than the utterance of the nerdy-sounding thing.
In contrast, Community takes the concept and builds into something substantial. They'll take "quantum superstring theory" and, for example, turn it into an episode where the vibrations of silly string perfectly predict events going on elsewhere on campus.