Hirhurim has been writing a lot about the direct and indirect problems posed by mixed dancing. Meanwhile, for reasons that require serious thought, Israeli Orthodox society has developed a full scale disco culture for singles, which presumably includes mixed dancing (or jumping, in line with the latest trends).
You can read all about it in Ma'ariv NRG and check out a full web site on the topic, called Dosibot. I"m really not sure what to make of it. I welcome observations.