Is this what's converting these days? It seems everybody's doing it. saw a gallery on the hun that led to this tour:
http://www.qmov.com/tour_blowjob.php?
Having one sample and then featuring tons of series snapshots down a column, so much of it that one has to scroll down.
Personally I do find these previews more enticing than what was going on previous...the 'next' show a few pictures and then another 'next' button to the join page.