So everyone who has problems with it not saving:
I was up to level 24 then had to clear my cache, it wiped out my save file. Took me just over three weeks of light play to get there, brilliant rating to lv 13.
Previously, I had cleared my cookies and then came back to the site, only to find my file was still here.
As a side note as I cleared my cache I also reset my modem, possible effect related to that.
Therefore: My conclusion is that we lose our save files if the cache clears itself. Mine is set to never clear giving me a total size of well over a gig of stored data. Keep in mind the possibility that resetting your modem might trigger the clear as well. Hope this helps to answer this question we have.