Would a live chat option work?

You're right @zoffiel.  Sometimes I click on a post and have no idea what it started as without going back (and I'm a very impatient person) but I'm definitely an offender when it comes to going off topic although it often seems relevant when I'm typing it.  But I have to say that your humour, appropriate or not, in my experience is very welcome - it often helps to take a shot at something while you're screaming, and can make a big difference as to whether you sink or come up for air.
So, it's knowing when to draw the line, I think and take a convo off to another space.