For starters, both of them seemed to love the anonymity that came with using social media, and to their advantage.
Everyone's mighty excited about the announcement that You is coming back for a second season on Netflix. To refresh your memories, Penn Badgley plays the role of Joe Goldberg, a stalker who has an unhealthy obsession with his girlfriend Beck. Soon after the first season of You aired, several people noticed how similar Badgley's character in You is to his character in Gossip Girl. In both the series, it seemed like his characters needed the aid of social media to survive. Both Goldberg and Humphrey needed to know what was happening with the others in the series. You did notice it, didn't you?
In You, he used it as a tool to keep track of his girlfriend, Beck, at all times. He'd get himself a duplicate of her phone, so he knows exactly who she's talking to or who she's with. Grade A invasion of privacy. In Gossip Girl, Dan Humphrey was referred to as the 'Lonely Boy' from Brooklyn who found himself amidst a group of rich snobs from the Upper East Side with scandalous lives.
Badgley's characters in You and Gossip Girl hid behind the anonymity social media provided them with to get inside scoop into the lives of other people. It was revealed in Season 6's finale that the spiteful Gossip Girl who let out everyone's deepest, darkest secrets was none other than Dan Humphrey himself. He did not care about the damage it did to their lives or its consequences; all he wanted was to be an insider, and not be treated as the 'lonely boy from Brooklyn' anymore.
Not just that. In both the series, Joe is pining for Beck, and Dan, for Serena. In both the series, he's the smart, quiet guy. The unhealthy obsession with these women is what basically leads his characters to do unreasonable stuff, like killing people to keep Beck safe in You, and by trying to distance Blair from Serena in Gossip Girl. In both the series, Badgley's characters would go to great lengths to make sure the women he's interested in were distanced from their circle of friends as he wanted them all to himself.
In You, Joe genuinely thinks of himself as the good guy, and constantly justifies his actions by claiming it's all to keep the love of his life safe. Dan was a harmless low-level stalker who always thought how unfair life was to him, to be put into a school with a huge class-divide, but he was quite harmless when compared to Joe. Also, the similarities between both his characters aren't something his fans have made up, Penn Badgley himself agrees there are similarities.
In an interview with The New York Times, Badgley said, "First of all, any part of me that was resisting the Dan Humphrey comparison has stopped because I’ve come to recognize how much of this is a surreal progression of Dan Humphrey. He’s the very special white man who somehow thinks that he’s an outsider, and it’s like, “Bro, you’re not an outsider — you are the inside; everyone else is on the outside.”
"It would all be so comical if it wasn’t also the generating impulse for so much prejudice which can get translated into violence. I think there’s a way of seeing Joe as the first time we’ve represented this kind of character in a responsible fashion, because to the degree that we are making him romantic and charming and glamorous, we are still being like 'Yeah, but he kills four people and then Beck. What more can we tell you about his character than that?" he added.
So what exactly does Penn think of his character Joe? "To me, Joe is this work in progress in dismantling and dissecting the myriad privileges that a young, attractive, white man carries with him. I’m not suggesting that the rest of the world shouldn’t have these so-called privileges. But I think when only one group has them, it’s actually horrific blindness when it comes to being in touch with humanity. I think it’s a material privilege but it’s not an emotional or psychological or spiritual privilege, and it seems that that can be great bondage," he said.