Facebook vs. LinkedIn: Which is better for business?

Preston Gralla and Jake Widman's article in Computer World describes 6 business scenarios and compares the use of the social networking sites, Facebook and LinkedIn, to solve them. These are:

1. Look for a job without your boss knowing. The answer? It's a tie - LinkedIn seems to have better job search services but it's much easier to use Facebook anonymously for this sort of task.
2. Find information about a job you're being interviewed for. The answer? LinkedIn - both sites are good for networking but LinkedIn provides more chances of finding and communicating with the right contacts.
3. Find a contract worker for a 3-month Web project. Facebook comes out ahead here - its networking abilities are better and cheaper.
4. Solicit ideas and discussion from team members. Facebook wins here too - it's set up to allow communication within groups of people while LinkedIn is focussed more on the individual.
5. Get feedback on a nasty IT problem from peers outside the company. LinkedIn is superior here - it has an Answers area where you can post a question to your network, categorise it eg by subject and see what others say about it.
6. Keep track of former associates. Another tie here - networking is what both these sites do.