OBTW, just to keep the record straight, most large forums that are not part of a commercial software or hardware company, pay for advertising. I see their Adsense ads all over the net. LQ is one example. There are myriad others that do.

We have run Adsense ads in the past on other web sites. It can get pretty expensive and the results are mixed.

We had the largest number of actively monthly users when we were sending out automated reminder emails to inactive people, but we stopped it because of a few complaints about the emails.

I agree that being welcoming and accommodating to novices and new members (all members) is what keeps the community growing. But there is also a difference between keeping registered users who have posted to post; and getting visitors to register. We get huge amounts of visits each month, millions of unique visitors each month. Most find the answer to their problem and never register (that is a "good thing") and some register, post one question, and don't return (honestly, I have done that countless times as well with working a specific problem).

So how do we keep registered users participating? That is the question, I think.