A blonde hides her supernatural powers from the rest of the world while her show deals with social issues through metaphor and analogy... Sounds like Joss Whedon's Buffy, but Elizabeth Montgomery was there thirty years earlier with classic sitcom Bewitched.
My theory that Bewitched was the Buffy the Vampire Slayer of its day started, I admit, as a half-assed joke, but the more I thought about it, the more it made sense. It's not just that Elizabeth Montgomery was the Sarah Michelle Gellar of her day - albeit with a nose wrinkle instead of a stake, and much less annoying - or that Bewitched made fantasy mainstream in the mid-60s much as Buffy did the same in the late-90s (albeit in a more underhanded, more comedic way), either. Let us compare and contrast:
Samantha Stephens, Meet Buffy Summers
So, both Sam and Buffy are both modern women who just happen to be the latest in a long line of supernatural beings who have to hide their true selves in order to fit in with everyone else. They're both the strongest, most capable people in the room at most times - although both look for guidance to authority figures in times of trouble (Giles is the modern Dr. Bombay!) - and have issues with occasionally over-bearing mothers and comedic foil main men in their lives, although Buffy had the common sense not to fall for, or marry, Xander.
Maybe more importantly, both Buffy and Samantha were torn between two worlds; the mundane reality of most people and the supernatural "truth" of their natures. But, in both cases, they don't really belong to either world, and just want to be themselves, and that's the main thrust of their respective series, no matter how disguised they may be with recycled I Love Lucy plots or prosthetic make-up monster of the weeks.
Magic As Metaphor
Of course, by the late '90s, television was much more able to address "social topics" without worrying about pissing off sponsors, viewers or censors, so Buffy's track record with using magic as metaphor for real life is potentially stronger and certainly more obvious than Bewitched, but that's not to say that the latter show didn't try it, nonetheless; the first season episode "The Witches Are Out" substituted bigotry against witches for racism, and the entire show has long been the subject of a rumor that the witch/human marriage was really about the perceived difficulties of interracial marriage at the time. If true, it's certainly up there with Joss Whedon's "horror as high school" metaphor...
Girl (Magical) Power
Lots has been written, talked and, yes, even blogged, about Buffy's (post-)feminist qualities, but Sam was there first; critic Susan Douglas argued in her book Where the Girls Are: Growing Up Female With the Mass Media that Samantha's "irrational" magic rendered the "rational" male-dominated society impotent, which was why she was constantly being told by Darren not to use them... although, despite her promises to try and behave, she couldn't quite help herself. As much as Buffy showed a more straight forward example of women taking control of their surroundings, Bewitched showed societal rules as ridiculous, and easily detourned and subverted by a more subtle form of female empowerment.
Don't get me wrong; I'm not arguing that Buffy in any way rips off, or was even directly influenced by, Bewitched. But, at the same time, it shares enough characteristics that, any time someone dismisses Bewitched as a lightweight comedy show that meant nothing in the grand scheme of things, I get overly defensive. Watch out there, buddy, I want to say - Well, maybe without the "buddy" part - Show some respect. After all, that's the first Vampire Slayer you're talking about.