well, that's another thing! I don't want to push my luck here, but "Re:", "Sv:", "Aw:" and other variants are a complete waste of time too.
Whoever thought "Re:" had anything at all to do with replies? It means 'About' and you use it - at least in traditionl paper correspondence - on any subject line, not just replies. In email subject lines it serves no useful purpose whatsoever. It's just noise. Junk. Interference.
The use of "Re: " (note the trailing space) in the subject line of replies is regulated in the Internet standard document RFC 2822, section 3.6.5:
When used in a reply, the field body MAY start with the string "Re: " (from the Latin "res", in the matter of) followed by the contents of the "Subject:" field body of the original message. If this is done, only one instance of the literal string "Re: " ought to be used since use of other strings or more than one instance can lead to undesirable consequences.
http://rfc2822.x42.com/#s3.6.5
anders ------------------------- http://anders.hultman.nu/ med dagens bild och allt!

