Big data/machine learning of all the meta data associated on tube sites, repurposing content for tablets, recommendation engines, social layers that are delineated/firewalled from the mainstream social graph, hosting/live streaming services for adult content -- are all opportunity spaces that come to mind.
Many of these projects can be kept on "life-support" and still bring in a healthy profit if set up correctly.
Please don't down-vote because it's porn - it's a legal and legitimate space