You have to enter you're name and email every time to comment on a post...
Yeah I know but you are still not logged onto the site, so as mentioned many may not be bothered about logging into the forums. If you have to log onto the site as a whole (including the forums) you might get more people on here, especially if you could encourage people more. For example, you could start by opening up a type of mailbag on here where anyone can ask questions. Another idea is to start creating some threads to get people's input and create a column from time to time to direct them this way.
I know you don't mind answer questions on there and you don't want to force people, but wondering don't you see the benefit of more active forums and less random questions below the columns? I feel the site would be better that way.