It's like the notion of "No ideas politics at the dinner table." Instead, the convention is to interact with some polite chitchat; a fact here, some gossip there. When all the time you're desperate to go to the pub and bash some ideas together.
At Oxbridge and other good places they know this, and have formalised it into something called 'debate'. It's quite something. You should have a look at it.
The internet could be a brilliant way to do it, except that it is open to aggressive people who actively fear ideas, and only feel comfortable trading facts. They could simply ignore the conversations about ideas that break out, instead of sniping..?