Reality Subtext: Lydia saying to Mary "you're related to famous people". In-universe she means because her cousins have thousands of people watching the vlogs. Out of universe, it's because she's played by Briana Cuoco - sister of Kayley Cuoco.
Episode 60 is going to be a doozy, because who should walk into frame of the very last second of 59 but William Darcy. In the credits hidden in the video's description, his actor is listed as "?"
Repeated in episode 97 when Darcy walks into shot in the last few seconds of the episode.
Word of God: Loads of it. They all frequently tweeted and wrote longer articles.
If we are to believe Maxwell Glick's opinion (expressed here), Ricky honestly means well, but he suffers from a lack of social skills and doesn't understand that he hurts others (whether it is because he is awkward or because he is too centered on his career and himself is still up in the air).
Even after getting called out in episode 64,Caroline Lee is still plotting against Lizzie according to the lead writer, Bernie Su.
Charlotte's remarks about working on Lizzie's diaries rather than her own videos in episode 42 were said in the heat of the moment. She really did consider the videos "their project" rather than just Lizzie's.