Q. What is domain tasting?My emphasis.
A. Domain tasting is the process of registering a domain name for a period of five days or less, parking it (showing ads), and seeing if it makes money. If the domain makes money, the registrant keeps it, if not, it is deleted and the registration fee is refunded back to the registrant. The registry (com/net/org/biz/info/us) allow for a 5 day grace period in which newly registered domains can be deleted for a full refund. Tasting only works in large volumes, which is why some registrars register tens or hundreds of thousands of domains per day.
I just checked a batch of identical spam I got. They were from a range of sequential domains -- new55flash, new16flash, etc. -- so I went looking. Yup, they're listed on a "tasting" site, where I got that explanation up top.
You know, I might like a filter that jails any mail from a domain that's existed less than 5 days. Hold it for five days and see if the domain is still there before dropping it in my inbox.