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."