I've seen the ad, and frankly I thought it was cool. I suspect that there are various reasons why Hillary chose to do the ad, and various interpretations of its meaning. In case you haven't seen it, it's a spoof of the final scene of The Sopranos, with Bill and Hillary sitting in the diner, eating, picking songs in the jukebox. Ann Althouse has an interesting analysis, but I think she reads a bit too much into it.
I think the problem of non-Sopranos watchers is interesting, but it's fair to say that Hillary made a safe judgment in assuming that the average person who would watch the ad probably watched, or at least heard of the show, and with the coverage of the finale, the reference was already out there. Of course, assumptions are by their nature fallible. I suspect the only ones who would think using a Sopranos reference is elitist, are those who probably won't vote for her anyway.
Ann's second point is entirely valid. Let us not forget that in the midst of this great story about these complex characters, that we're dealing with hardcore criminals. Tony Soprano is the protagonist, but he is the boss of an organized crime family, and Carmela turns a blind eye. We love these characters, but they aren't exactly role models. Such associations could backfire. You know full well how this could be spun.
The rest of it I'm not touching, because it reeks of reading too much. As one commenter put it, sometimes an onion ring is just an onion ring (BTW, the carrot really is a phallic symbol? I didn't know that!).
At the end of the day, just as the show was a show about family, that happened to involve mobsters, this ad was a clever way for Hillary to try to be hip, current, and edgy, I suppose.
And Johnny Sack was in it. That was cool.
Oh, and the comments are getting ugly on her blog, BTW.