When should a book NOT be sold on Ebay or Amazon or....?
Well, here's a new dilemna. I find a truly rare, very old book, one that lists for far more than any book I've ever found. I'm excited and then....I start to wonder if selling it online at one of my usual venues (Ebay, Amazon, half.com) is the right choice.
Perhaps this is a book that is too valuable to list on Ebay or Amazon. So I call a company which specializes in rare book auctions and they support my doubts. They have me send them scans of the book cover, sample pages, etc...and there is a very real possibility they'll be interested in auctioning it (I'll keep people updated as I get news).
They also tell me that there is "little to no connection" between the prices they can get and what the average seller can get on Amazon or Ebay, at least once a book is worth more than $1000.00 (and this one may be but I do emphasize the word "may"). I have to hear from their appraiser before I know if I have that true rarity, the kind of elusive find I've always wished to discover - and may have.
I'd be interested in hearing from others about their own experience with books that may or may not be "right" for the typical online book venues, especially if anyone has sold a book at an auction similar to Sothebys or that level of sale. This is a whole new area to me.

I recently learned a lesson (yet again) about the importance of keywords in auction listings. Recently, at item of mine at Ebay went from $99.00 (my opening bid, which was actually rather low for that book) to over $200 in the last MINUTE of the auction! Talk about shock....and there I was, naively thinking, "Well, guess I'll have to relist or put it in my store listings..." and then boom! Two bidders get in a sniping war in the last minute (and I DO mean minute, literally).
The book? ITem 200009171235, book title: Scouting for Stanley in East Africa. I assumed that most bidders would be interested in the author's search for Stanley (of Stanley and Livingstone fame) WRONG. The author, who made the first transcontinental bicycle ride across the U.S., was of interest to cyclists.
I lucked out because I put the word "bicyclist" in my subtitle for that listing (!). I would never have thought THAT would do the trick...but it did. Not Stanley, not Livingstone. Cycling.
By the way, the words in the title space? They were: Rare Vintage Travel Book 1890 Stevens. Notice the lack of a title? I still got a ton of "hits" (views from bidders) because there are plenty looking for "vintage travel books" maybe even MORE than are looking for that book under the exact title.
So....if you sell on Ebay....think about it. Title or keywords? If you can't fit both in that title space, sometimes a choice has to be made.
I'd appreciate hearing from other booksellers about this, pro or con.