If your forum has a lot of smart people, and they read the recommended readings, then the more people who participate in the forum, the smarter the forum will be.

If the forum can be said to have an intelligence which is equal to the sum of its parts, or even just some additive function of its parts, then yes. But this is not reliably the case; agents within a group can produce antagonistic effects on each others' output, leading to the group collectively being "dumber" than its individual members.

If those people aren't discouraged from posting, but are discouraged from posting stupid things, your forum will trend toward intelligence (law of large numbers, emergence with many brains) and away from being an echo chamber (law of small numbers, emergence with few brains).

This is true in much the same sense that it's true that you can effectively govern a country by encouraging the populace to contribute to social institutions and discouraging antisocial behavior. It might be true in a theoretical sense, but it's too vague to be meaningful as a prescription let alone useful, and a system which implements those goals perfectly may not even be possible.