Girl-Wonder.org is very cool. And as to my comment in the title:
Betty Kane (Bat-girl) was never taken seriously, and still isn't (although she's Bette Kane / Flamebird in the post-Crisis on Infinite Earths world).
Kathy Kane (Batwoman) was killed as a minor point in a not-particularly-memorable storyline, for no particularly good reason. She's back in some form post-Infinite Crisis, so we'll see how that goes.
Barbara Gordon (Batgirl I) was shot, paralyzed below the waist, and it was implied that she was raped. Although she's a triumph of characterization as Oracle.
Helena Bertinelli (Batgirl II), better known as the Huntress, was held to impossible standards far higher than any male Bat-sidekick and got fired pretty quickly.
Cassandra Cain (Batgirl III) made a triumphant moral point about not killing in the penultimate issue of her series, only to renounce everything she'd fought for over the years in the last issue due to her assasin mother's ideas and the bombing of Bludhaven. So she's an assasin now, just like mom.
Stephanie Brown (Robin IV), better known as the Spoiler, was set up for failure as Robin pretty much from the beginning in what appeared to be a cynical bid to lure back Robin III. That storyline and the one that led to her death pretty much ignored much of the character's development over the previous ten years. And she stayed dead while Robin II, whose death was actually a major event in the Bat-mythos, was revived, apparently just because it seemed like it would be cool.
Cass was awesome for a long time, but we'll see what they do with her now. Oracle and Huntress have become characters increasingly independent of Batman and his inner circle. So at least as their own characters they're now in good shape. But in both cases their times as Batgirl ended badly (Barbara was actually not even in costume/on duty when she was injured). And I'm still quite bitter over Stephanie.
So I really hope they're going somewhere decent with Cassandra's story right now. And I really hope the new Batwoman (apparently once again Kathy Kane, although possibly going now by Kate?) is a strong character, and isn't reduced to begging Batman to be able to keep her role. I'm a bit disappointed to hear that she'll apparently be a closeted lipstick lesbian. I was actually hoping they'd make her out, proud and a touch butch. I mean, that's not a huge stretch for a woman who goes out beating the crap out of bad guys, right?
Although given that almost all of the Bats are totally repressed, the closeted part might make sense. And maybe she'll come out and get a makeover...