"Domain tasting" refers to the practice of registering a domain name and then deleting it within the 5 day grace period for no cost. This allows to find out whether the domain name attracts users; by placing advertising on the page, domain tasters can also make money during the 5 days from pay-per-click ads (well, could, until Google put its foot down last year).

Because domain tasting led to abuse, ICANN implemented a penalty last year: registrars that canceled more than 10% of the domain names within the 5-day grace period would pay 20 USD cents per canceled domain; later, this fee was increased to USD 6.75.

The fines imposed by ICANN led to the virtual end of domain tasting: compared to last year, domain deletions in the grace period are down 99.7%. That's good news for trade mark owners, too, because the domains being tasted often contained protected terms (or were confusingly similar to high-traffic domain names).

Sources: Ars Technica for the image; ICANN report of 12 August 2009