I think you misunderstand me a bit in that I don't think there is a clear distinction between entertainment and the other functions of internet interaction. In this wise it is different from a medium like TV. Well, not exactly; that's too strong. When you see a TV program, for you it may be entertainment, but for those at the other end it mostly has other purposes (e.g., keeping the Nielsen numbers up). There is a component of entertainment (if that is the right word) in that those actually making the show may be pleasing themselves in doing so. But in an Internet forum, the situation is both more and less symmetrical. Everyone appears to come at the forum the same as you, but in practice they have a huge mixture of intentions.
And while there is something to be said for being freed from official channels, the flip side is that, for the most part, the official channels, as it were, don't want anything to do with the internet, at least not in terms of fora. And to be quite blunt, they don't participate because they don't have time or patience to deal with blockheads. They have day jobs with theology, after all. It's hard enough to deal with parish crises or problem parishs and priests, but then to go on line and have to deal with every opinionated kids with a modem-- it's just too much.
And therefore fora are full of opinionated hardheads, because the internet gives everyone an equal voice (at least in proportion to their willingness to type) and simultaneously makes it easy to walk away (if you aren't addicted, anyway). So there is every reason to be suspicious, because by and large the extremist positions will get more air time.
It isn't a question of sincerity. And I do think the issues of heresy can be ignored, because within the context of Orthodoxy heresy is inescapably a political issue. You must not trust that someone who brings up an issue of heresy is sincere-- you cannot even trust yourself. If you jump to every suggestion or accusation of heresy, you simply make yourself a pawn to everyone who uses it for any ulterior purpose, even if they aren't even aware of their motivation themselves.
That's precisely what's wrong about deciding the fate of the Church in a forum such as this. Orthodoxy, like Anglicanism, is supposed to be conciliar. This isn't even remotely a proper council; in this wise its closest analogue in polity is a Baptist congregation. And what is going to tend to happen is that discussion will tend to be dominated by the extremes, either those of authority, or those of rebellion. Here I think rebellion is winning, as evidenced by the drift of the top posters from ROCOR to dissenting jurisdictions.
I of course cannot claim in-depth experience in Orthodox theology; but my experience with internet religious discussion dates back to its earliest days, some two decades ago. I think in this wise I have accrued a depth of experience in the matter which you might do well to heed.
Anyway, to pull this back to the original point: a forum is the ideal place for the rebellious (especially the authoritarian rebellious) to transmit every little issue all over the world in a flash, without any moderation in terms of its proportion. And in Orthodoxy, such moderation belongs, by right, to bishops. Even if they are not utterly trustworthy (and I agree, they are not) it seems to me that, from an Orthodox perspective, discussions in a forum tend to transgress on their authority more often than not.