There are a number of Meta posts about flags, both here on Meta.ELU and on Meta.SE. Do we have any guidelines for flagging comment as offense? (mELU) Why can’t I flag a question as offensive? (mELU) ...
A question of mine has been suggested to migrate ELL site, Why is there two Q&A sites for English language? What can I ask on each site?
Questions that can be answered using commonly-available references are off-topic. What good reference works on English are available online, and what kinds of questions are they good at answering?
Abbreviations are always a potential source of confusion. Some people might happen to know what OED stands for, and can figure out what NOAD must mean, but others may not be so lucky. Googling for PIE ...