When it is not immediately apparent to which conversation or to whom a comment is directed, "wrt" is used.
JohnQ Public: "I am looking to buy a new HDTV and I would like to know the
best display technology."
SoAndSo: "JohnQ Public, That is a difficult question to answer; budget wise, however, CRT and LCD HDTVs are a clear winner."
RandomPeople: "... <
unrelated conversation> ..."
...
SoAndSo: "CRT or DLP wrt HDTV contrast
ratio."