Thing 22 is about volunteering to get library experience.
I have mixed feelings about this subject. Many libraries don't even accept volunteers, but if you are lucky enough to get a volunteer gig it's probably not going to be professional work. If you have no library experience whatsoever it will be great just to gain experience working in a library, even if you're just shelving books. I've never had to do this because fortunately I had a job in the library when I was an undergrad so I had experience under my belt long before I decided to become a librarian. I've done other volunteer work though, most notably as a board member and committee chair for East Somerville Main Streets. Some of the more library-relevant aspects of the job have included organizing a series of networking events for businesses and putting together a monthly newsletter.
From the hiring standpoint, you need to be careful about depending on volunteers. It's difficult enough to convince municipal governments that we're important, valued professionals in the community; we shouldn't have to also convince them that they need to pay us. Why pay MLS salaries when there are people willing to work for free? Sure, there are plenty of people who want to volunteer in the library because they think working in a library is "fun." That doesn't mean they are good at it, or will stick around to deal with the less "fun" parts of the job. There is training involved, and investing the time and energy into training a volunteer is totally worth it if they stay for a while, but if they get bored or find a full-time job or leave for whatever reason, then you may not have gotten payback on your investment.
If you're thinking of volunteering to gain library experience, you may find it difficult to find an opportunity. But keep your options open - perhaps you could create your own volunteer job. There are many venues where there is no library funding and free help would be the only option. Look at all libraries popping up at the Occupy locations, for instance. Offering to set up and maintain a library for a senior center or other non-profit organization would also be a great way to get some experience while helping to provide much-needed services in your community. You'd probably be performing a higher level of work than in a traditional setting where there are already paid librarians, and showing off your ingenuity and ability to plan and execute projects.
Have you done volunteer library work? What was your experience like?