I loved this! I felt exactly like you did when I saw the episode.The two of them were definitely flirting (heavily flirting) and when Dan came over I was like"Go away Dan.Leave them alone" And Serena and Vanessa seemed to be saying the same thing.
I think the two characters have incredible chemistry,and I'd be happy to see more stories of the two of them. I love Serena and Blair,but I could see Vanessa appealing to Serenas' adventurous,wild side.