I have no sources and the following is mere speculation:
Even before the heter to write Oral Torah was enacted, people certainly had notes written down for their own personal study. (See Rambam, intro. to Mishna Torah.) And one can only assume that sh'ailos and t'shuvos were written back and forth between communities that contained rulings and explanations of the Oral Torah.
So what is the difference between those writings and the writings that were prohibited before the heter? I would say the difference is that the notes and t'shuvos were written and kept with the intention of personal reference and study and not for public consumption. We do not find that books of sh'ailos ut'shuvos were written and published, since these were considered private texts, to be viewed by the intended recipients.
The books we have today, on the other hand, are texts that are written and published with the intention of being read by a public audience. They are permitted to write so that Torah not be forgotten, or even just for the purpose providing texts from which one may study Torah. (See here.) Even the published sh'ailos ut'shuvos are intended for public use and study, which makes them part of the now-written Oral Torah.
Now, where do this and similar websites fit into this picture? If this was strictly a question-answer site for personal rulings and explanations of Torah ideas directed for personal use by the asker, it would probably not even be a utilization of chazal's original heter. It would just be a modernized version of the old sh'aila- t'shuva method. However, since all answers are online for public viewing, and not only that, but intended to be a method of Torah learning for others interested in the topics addressed here, it would seem to be at the same level as all the other contemporary published Torah books. Even more so the non-Q&A oriented sites, like those that simply publish Torah content online.
The only way I can see to go "further than the original heter" is to publish material that contains Oral Torah, but is not particularly intended for Torah study and reference. This site would certainly not fall under that category.