What's up with the ridiculous offers?!?

The OP may well have been one of those dealers who lowball offers here in order to buy cheap and resell that have been mentioned.   Trying to deter the competition.

You don't have to respond, and if you decide to respond, just say thank you, no.  No explanation required.

An item, any item (car, watch, art, audio equipment, camera, etc.) is worth exactly what someone is willing to pay. Regardless of what you feel the item is worth is really irrelevant.

You can post the item and list a price and the negotiations start from there.  If you are firm in your price, then say that, and ignore anyone that lowballs. 

If a buyer is really serious, then they will contact you with a serious offer.

I collect rare books, watches, classic cars, etc.  I can tell you there are two types of buyers.  1) the collector and 2) the dealer.

The collector wants that item and is willing to pay near or above market prices for that item.  The dealer simply wants to flip the item and therefore, they want to pay pretty much nothing for it, then turn around and flip it for as much as they can.

No difference in the audio industry here on audiogon.  You don't know whom you are dealing with. I try to not be desperate to sell something and therefore, I can list the item at what I feel is a fair price based on market values.  Maybe slightly lower than the average market rate and I typically have no trouble selling the item.

I ignore the lowballers that come in with stupidly low counter offers. 
Someone will eventually want the piece.

enjoy

i acknowledge , by any accepted standard, acting  that this is american and a buyer should be free to make stupid lowball offers, which the seller is free to ignore. however, some of us still cling to the illusion that audiogon, as opposed to other marketplaces, is (or is supposed to be) a community of enthusiasts who are bound by some code of courtesy and fair dealing. hence i get more annoyed than i should at buyers or sellers who, by any accepted norm, making dumb offers.

Meh not that big a deal, I either decline or make a reasonable counter-offer. Seriously nothing to lost sleep over.

"Is this a new feature in Agon? Listing AUTOMATICALLY negotiates by itself once listed?" 

No, but listing something for sale commences the sales process thus is the start of the negotiations process because the seller is posting at a price point. 

I do do not and have never advocated negotiating against ones self