Vanessa shows up at Nate's house wearing the mask, because far from her being in physical danger like you might have hoped, this was a little joke at Chuck's response. And what do we do about jokes? Oh, how we laugh.
"Turns out I can still apply to Oberlin," B says darkly, and S sits all sad with a secret in her phone. B, of course, assumes that S is feeling shitty because of Blair's expulsion, and S finally blurts out that she was right about Dan and Rachel. "Seriously? I must've picked up on something!" But then she's sad again, because they need proof. But then she's happy again, because S's sad face says they have proof. But then S doesn't feel like that would be a good move, but then B tells her that confirming the details with him would just "give him another opportunity to lie" to Serena, which -- since in this episode S is as cartoonishly stupid and gullible as B is cartoonishly stupid and bitchy -- convinces her to turn it over. "How awful!" B says, sparing a moment's sympathy about it, and then going right back to scheming: "But this is the smoking gun I've been waiting for." Serena gives a half-hearted protest, but B is off. "We have to get to that meeting. Dorota! Go get my dog back!" S texts Lonelyboy to meet her at Constance, with the angriest ASAP you ever saw in text form.
Harold explains that it's ridiculous for the school to think it can control what children write on a public site that has nothing to do with school, and then Rufus offers his professional, incorrect legal opinion that what B posted was slander, and a school board lesbian yells about seeking an injunction against Gossip Girl and shutting her down, which makes Lily laugh because that's dumb as hell and a million copies will grow back in its place, and Rufus is all, "This isn't some note on the bathroom wall, Lil! It's on the internet!" Which is exactly what you would expect Rufus to say, because he's old and clueless and looking for attention, but doesn't change the fact that the internet actually is just a very large bathroom wall, and anybody who cares about this shit or goes after their employees based on it has bigger problems than their basic inability to understand how the world works. Lily points out that Yale is a sort of steep price to pay, and Rufus goes, "What about Dan's future? How long is this gonna follow him?"