PG, VG, PV and more...so confusing. I ordered PG liquid, now I see others recommending different. What is the difference and what do all the abbreviations mean? If you order flavored liquid, does that contain nicotine also or just the flavoring? I'm sure this is covered somewhere on this forum, but there is so much info, I'm on info overload right now. Is there a thread just giving abbrevs and what they stand for?