Private message without an announcement in the thread is the best way to do it. Often times like in this thread, the original poster is just looking for information about a particular part. I often suggest early in the thread that the op start a wanted ad. In a perfect FABO world every part that is needed starts out as a wanted ad and every part that is sold starts as a sale ad. What goes on behind the scenes is unknown to the public but then there is no written record of the transaction if it goes bad. It's just rule following and moderator stuff.
