Originally, "flame" meant to carry forth in a passionate manner in the spirit of honorable debate. Flames most often involved the use of flowery language and flaming well was an art form. More recently flame has come to refer to any kind of derogatory comment no matter how witless or crude.
FLAME
Русско-английский перевод FLAME
Русско-английский электронный словарь Edic. Russian-English dictionary Edic. 2012