This is perhaps a highly ambiguous question, so let's use an example.
say I have stumbled upon this new billion dollar idea which is stackexchange (assume it is exactly what it is now just that it hasn't been created yet), I have done a brief patent search and it appears no one has done this yet, and I have covered all the angles, from the creation of multiple modules based on topic (computer, patents etc), to the idea of using the up/down arrows to mark a question's worthiness. Basically, I have this product (or project) all mapped out, and all we have to do now is to roll up the sleeves and do it.
now assume that I wish to file a provisional patent application to lock in an prior date for this wonderful idea, but immediately there are problems,
which exactly the aspects of stackexchange can I use as claims? also, while we are certainly going to include as much description and detail of the functionality of the software as we can in the specifications, there are certainly thousands of ways to describe the same process from different perspectives, how can I be sure that my description is the most "legally correct" one?
and this brings us back to my original question, just how serious a provisional patent application is? Undoubtedly, the more it looks like a non-provisional patent, the better. But if this is the level of prevision we should aspire to then why not just apply for a non-provisional parent directly? so from a functionalist perspective, is it right to think of the PPA as somewhat an "official memo" sent to and kept at the patent office, so that within a year you could file a non-provisional and point to the similarities it shares with the "memo" so as to demonstrate the original idea was invented several months (but less than 12) ago?