I've used Wordpress and it's good. If he's got a basic scripting background and wants something really custom django is definitely the way to go. If you don't want to mess with scripts, I'd say Wordpress.  
 
Not sure what features Expression Engine would have that would be a tipping stone for your friend, but really the above options seem reasonable.

Perhaps how much benefit of the doubt is a function on the cost of giving it? It might be easy to see a picture and send a message to someone potentially cute, but I imagine the scrutiny would increase as costs such as transportation, long distance phone fees, or paying for dinner go up. 
 
I'm really interested on how women see that differently. Also, I wonder how much benefit of the doubt is given to profile information as opposed to the picture - is he really making 100k+?

This sort of stuff is always interesting to me especially as a Catholic that double majored in religion & bioanth. Every time evangelicals changing society comes up, I can't help but think about C.S. Lewis thoughts about marriage in Mere Christianity. In his view, "christian" marriage should be kept very separate from secular marriage laws and those laws shouldn't try and impose a lifelong christian commitment on non-Christians. The idea being that if Christianity truly is different, truly is a choice, laws that force it on people demean the message and does more harm than good. He expands that to much more than marriage. 
 
I think whether or not it's a revival of reading Lewis, that sentiment will creep back into the mainstream view.

Linking it to "social display" is right on. While talking about more scholarly subjects may often seem to be on a higher level - I think often it serves the same purpose as talking about LeBron James wearing a Yankees Hat or whether or not Journeyman is Quantum Leap 2.0. All usually are good indicators not only of effectiveness of forming an argument, being concise yet complete, and listening skills.