During the 2007 year I consulted with a client on the purchase of an available domain name through a private party. We came in a little under the asking price with a solid deal. We lost the bid.
In the process, I described to the client what "might" happen if we didn't win the bid. I played out different scenarios for the client based on what the purchasing party might do with the domain. Guess what? It happened just as I described it would.
We had major plans for the domain if we got our hands on it. So did the other buyer. But, their plans were bass ackwards. They took years of history and pretty much tanked the entire domain. Not only did they drop a bunch of links to other properties, they have major technical issues which are dragging it further down in the SERPs.
Moral of the story? If you are going to purchase a domain that has long-standing history, careful planning needs to go into the transfer of ownership and how the transition is to be handled. I can honestly say that the other buyer did everything you could possibly do wrong in the purchase, everything!
I know what they were thinking. We'll buy the domain, put links up to all of our other existing properties and feed off of it. Problem is, as soon as the domain changed hands and the site profile changed (through content changes and outbound links), the food source was short lived. In a matter of 60 days, the domain in question went from healthy page one positions to page five at the moment. It continues to drop through the SERPs each week.