chris
if you check now they will have sold them on or have then up for sale at some large amount. never let domains go my friend. they become worth more with age. its not what they have done as far as traffic its the age. Google looks at old URL's favorably.
when i let the allergstop one go they had it up for sale for about £600 and while they where waiting to sell, they sold advertisements on the home page to allergy companies. JB thought it was me and was going to slap a court order on me. it was had to prove that i let it go, as whois takes time to update.
respect
ian