[enahs]

ecause my analysis found, the a majority of guests arrive, at least for the first time but not only, via an external search.

I have no doubt that this is the case. Whenever people need to know something, they just type the question in google. For the freshman college level and below, virtually every question is probably answered somewhere on the internet. Chemical Forums just happens to be a large and diverse chemical site, and so it will come up quite often in a search.

I would bet a couple of beer's  that a virtually all the non-members that browse this site (excluding bots of various kinds) are people that find answers to their homework questions via a google search.