Anyway it seems that this future is quickly becoming a reality, with rumours that Google to provide listings search. Joel does a good job of highlighting the relevant parts. While the item in Red Herring does not specifically mention jobs, they are an obvious move as there is real revenue to be had.
So what about the new entrants to vertical search and the dot jobs domain? In the end I do not think it will matter. Yes dot jobs will get a higher ranking in search results, if SHRM can keep the integrity of the TLD. The real impact will be is for the job seeker, this was highlighted by John Sumsers also mentions this in Driving Traffic 5. As both Joel and John mentioned if Google start listing jobs then search engine ranking will become a major factor. This will mean that recruiters will need to understand enough about search engine ranks to be able to work with the IT professionals who run their job sites to ensure the best ranking possible.
This will scare many recruiters.