The IMC has the ability to apply Internet style quoting to reply and
forward text by inserting a greater-than sign (>) before each line of the
reply or forward text in messages sent out over the IMC. This allows the
recipient of the message to easily determine which part of the received
message was added to by the sender of the message.
This function is controlled by the following registry entry on the
Microsoft Exchange Server computer running the IMC:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIMC
\Parameters\UseRTFText
If the value of this key is 1, Automatic Prefixing is turned on. This is
the default. If the value is 0 or the key is not present, prefixing is
turned off.
The character used as the prefix is not configurable. It is hard coded to
be '>'.