Question About Ebay Lingo

There was a cover recently on ebay (since ended but you might be able to find it) from Knoxville, TX and the seller had "DPO and RF7+) in the description.
What does that mean?
I sent the seller an email and haven't gotten a response (yet), curious because I sold it to him and I'd like to know what I am missing?
Thanks
Dave

DPO, as I learned in a thread of mine, I guess is a discontinued post office.

Thanks! Any idea about the RF7 designation?

It may refer to the rarity factors in the 8 volume Helbock series listing every Post Office in the US with dates the office was open plus a rarity factor. It is a scale to 10 with ten being the scarcest and I believe zero for a currently open Post Office. DPO is a standard postal history term for a Discontinued Post Office which is consistent with the RF7.

Wow, thanks WT. Would you happen to have said catalog or know if it's available online? I may have a few post offices I need to look up (especially since it appears there are collectors that look for that type of thing).

Thanks again!

Some town postmarks have limited use and are assigned value guides or rarity factor.
Richard W. Helbock's United States Post Offices lists every U. S. Post Office that had operated up to 1990's and gives them all a Srarcity Index S/I of 0 thru 9. DPO's are sought out.

Answered while I typed. Although he uses Scarcity Index or S/I rather than rarity factor.

One ebay pet peeve I have are sellers using shorthand lingo like this in the title and description with the assumption that everyone viewing knows what they are talking about. Some of these sellers are probably specialists who become immersed in their specialty and do not realize how incomprehensible some of this stuff is to casual viewers.

To the best of my knowledge it is not available online. Literature dealers have them in stock from time to time. The 8 volumes are broken down by geographical area, such as the West, the Northeast, the Mid-Atlantic, etc. They do come up on E-Bay once in awhile. Some volumes exist as Excel files, but not all.

Leonard Hartman has all eight volumes in stock.

http://pbbooks.com/statea.htm

I don't trust officials who use acronyms without explanation, and I wouldn't bid on a sale item that used those terms.

In United States Post Offices, Volume II - The Great Plains - Knoxville, Tx is listed as being open 1854-1875 and has a S/I (Scarcity Index) 7. In the introduction it states that postmarks in this volume have a demand factor of one, unless from Oklahoma which has a demand factor of .75. S/I is to be multiplied by the D/F (Demand Factor) for the Market Value (M/F). In this case a nice cover from Knoxville, Tx would have a M/F = 7 which means a value of $100 to $200 to a buyer who is looking for that cover. Demand Factors change and this book was published in 1998, almost 20 years ago. Jim Forte's web site (http://www.postalhistory.com/State/...s/index.htm) will give some idea as to the current popularity of a state.

Thanks again all and especially WT. I can tell you I sold the cover for $5 and he sold it for $15. So nowhere near the "market value" as determined by the formula.
Since you seem to have the knowledge, can you tell me about Fort Griffin, TX (from the Helbock if you have it?)
Thanks again!