A very large part of getting to know people is being sensitive to what people are comfortable with, and that varies from person to person.
As for the monthly usage, yes, that's a good point. Before I got involved here, my normal monthly usage was 80 to 90 hours. My price plan gave me an allotment of 150 hours, for $16.95 USD a month. When I saw how my usage was increasing, I ordered a change in plans. Beginning on July 12, I will have unlimited hours for $21.95 a month. The problem is it's July 2, and I have about 27 hours left now. The penalty for exceeding the allotment is $.99 per hour, any fraction of an hour being billed as an entire hour. I may be an American, but I'm not a rich one.
As for the social nature of the forums, I agree, that is, indeed, the charm. There are those times, though, when private dialogues interrupt a thread, and isn't that what the PM is for, i.e., to avoid the accumulation of posts that are extraneous to any thread?
But again, there's the comfort level, or comfort zone thing. Personally, I wouldn't post anything on a PM that I wouldn't post on a forum thread. To me it's just considerate to take an aside with someone, when it's called for.
The forum games are a good example. Answer the Question? Do you pause before posing a question, and ask yourself is it a question you yourself would feel comfortable with answering? The political forums at times are little more than shouting matches. The chit/chat are, as a rule, civil and reasonable. But I think the heart and soul are the games. People are honest, and treat one another with respect. There is clearly a lot of trust. Without trust, without that certain precious naivete, the games would falter and die. Let's see, we got honesty, respect, trust--hey, isn't that called love? In the very best sense of the word, is this a Christian forum?