ICANN decided to open a virtual Pandora's Box and approve the sale of any domain name that can be dreamed of. While it's no secret that the existing domain space is really REALLY crunched, letting imagination run wild seems to just be another invitation for spammers and phishers to snap up domains by the thousands. It should also be noted that a fair number of anti-spam and e-mail verification systems depend on a known list of valid domains to help speed up lookup times. I'm also wondering how the DNS root is going to look now. There's already been concern that the root servers are heavily taxed and adding a significant number of new registrations is going to make DNS much trickier.
The move is intended as a revenue generator. Companies can pay anywhere from $100K to $500K for the privilege of being the sole registrar of their own TLD. There are some important restrictions: no copyright violations and squatting, nothing similar to an existing TLD (no typo-squatting), no registrations for communities or companies that don't exist and the ever-nebulous nothing immoral. There's also an application and review process.
I would note that the last attempts at creating new TLDs was a fail. Almost as soon as they were introduced, .biz and .info were overwhelmed with cybersquatters, spammers and all kinds of nefarious elements. TLDs like .travel haven't taken off either (yuk, yuk). Despite a run on .com, .net and .org addresses, many companies have gotten creative by using international domains (last.fm, del.icio.us, etc.) and creative company names (Flickr, Meebo, etc.).
Not all is bad, however. ICANN also voted to move forward on allowing domains with non-Latin characters including Chinese characters or the Cyrillic alphabet. I'm sure there's a lot of non-western countries who are pleased as punch at the idea of having domains in their native tongue. And domain tasting? Arrowed! Apparently the spammers would keep on passing a tasted domain back and forth between entities, keeping the domain locked up for months or years without paying a dime for it.
Anyone who operates network equipment should be doing some upgrades Real Soon Now(TM) to avoid problems in the future. Adding UNICODE support and ditching reliance on a fixed list of valid TLDs would be highly recommended.