To your question, forum participation leads me to revisist the Scriptures over and over, which is faith building. My desire is to contribute to the body of Christ by my participation, and I know to do that I need the Holy Spirit directing my words and my thoughts, and I have to trust Jesus to live His life through me, and that is faith building.
Yes, these two debates seem to dominate many threads. But outside of those debates, I find many other ways that I am edified.
Sharing about myself, others sharing about themselves, our unity is increased. As we continue to be taught by each other, we learn new things, our understanding is increased. As we are inspired to make changes in our lives as we see the day drawing near, or as we see the need of greater love, or whatever it is, we increase in sanctification. As we pore over the Scriptures to know the meanings of these things we increase in the renewing of our minds.
All of these increases are the work of the Lord within us, and as we see in our lives the outworking of His promise our faith increases.
I think when God's children gather together in whatever fashion they may, it's a good thing!
Much love!