Question RE GoDaddy Domain Buying Service: Offer Made on Domain $20,000!!

I have owned a domain for around 3 year.. It is a pretty good .com - and i can see there are opportunities to use it for a big site. Recently GoDaddy's Domain Buy Service sent me an email that an offer has been made on the domain. I checked this morning and it's a $20,000 offer!!

The domain is actually on 1and1.com - and not on godaddy auctions.. but the email from godaddy is legit.

does anyone have any experience of this.. and what is the best option.
I'm thinking do i just 'accept' (yes.. the cash would be great!) - or do i move it over to godaddy auctions and auction it quickly while there is interest.

Does anyone here have experience using this "Domain Buying Service"?

The email i got is below.
thanks!!!!



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The current offer for XXXXXXXXX.COM is: $20,0000

This initial offer can be accepted right away! If you feel this is an acceptable offer, click "Accept Offer" so we can get started with the payment and transfer process. As soon as the process is completed you'll have a little more money in the bank. It's that easy!

If this offer isn't quite what you are looking for, click "Counter Offer". We'll contact the buyer to see if they are willing to meet your desired price, or generate a new offer. This way you can let the buyer know exactly what you would like to receive for XXXXXXXXXXX.com (MY DOMAIN).