"Tell the Reader in the Body of the Message What You Are Seeking
Once someone has opened your message board posting, you need to communicate exactly what you are seeking. That also should include any information you already know as well as any resources you may already have exhausted. This will prevent a reader from duplicating the efforts you've already expended. This is a very nice courtesy.

The body of your message may include more information about the person or family for which you are seeking any information, including names and nicknames, vital dates, and places. It is better to provide more concise details to indicate what you already know that to omit what you feel is obvious.

It is important to organize your message in such a way that it is logical and easy to understand. A wandering diatribe will lose the reader's interest, and he or she may not even be able to determine what it is that you want to learn! Here is an example of a body text of a message board posting that I made:"

"I am seeking information about Jesse HOLDER and his wife, Hepsebah (Hepsevah?) who lived in Gwinnett County, GA, in the 1830s and early 1840s. They produced at least two sons, Green Berry HOLDER and John Thomas HOLDER. I am descended from Green Berry and have all descent there, and most of his brothers. I am looking for more information on Jesse and Hepsevah (maiden name unknown). Thank you."

Source:
Along These Lines by George Morgan in Ancestry Today