Why is the eminent demise of job boards consistently thrown at the feet of social networking sites? Why job boards? Should then all sites who attempt to engage two interest parties bow to the social networks?

Fact is, the social networks are awesome and amazing at what they do: being
social networks.  Their challenge is how
to effectively monetize their assets.  Posting
jobs seems an easy entrée and with the tools available, anyone with a website
can do so. However, no social network has provided a platform rich enough to
maximize the user experience and reach critical mass, and at times many seem
confused and clumsy in their attempts. 
Why?  Because they are social
networks, not job boards. 

Search Engines:

There is a lot of chatter about search engines replacing job boards. I agree that they are often used as starting points. However, when you use a search engine to conduct a job search the vast majority of results
originate from job boards. As for job search engines doing in the job boards,
they are great for what they are and certainly have carved out a nice place in this
space that will continue to grow. However, as valuable as they are, as a standalone
they are limited by design to offer the user the best possible experience and
search filtering.

“Walk up Hill both Ways” Recruiters:

The recruiter who feels the need to walk both ways to work, uphill, barefoot in the snow, and insist that their clients would not pay a fee for a candidate sourced from a job board is missing out on a significant source
of revenue.  When I was recruiting I never had a client ask me the source
of my candidates; they don't care.  So long as you are making their job
easier, they are getting the best candidate and that candidate says
"yes" to their offer they are happy.  Further, I assure you that every
recruiter has placed a candidate from a job board, social network, directory, referral,
etc. that was already in your clients database. The job of a successful
recruiter is to not simply generate resumes but to source the best candidate by
any means possible and manage the process for their clients.  Therein lies the value. 

I’ll prove it.  Before the internet how did recruiters source candidates?  They placed ads in newspapers, bought stolen company directories and used their referral network. 
All these tools were available to internal recruiters, too.  We all use the same tools, whether it is 1976
or 2010.  The truth is, given the same
set of tools, recruiters' proficiencies vary and the most successful recruiters
use every tool in the tool box to the max. 

The “I work Linkedin.com” Recruiter

I hear it all the time…”I will only work with passive candidates, no job board candidates for me, I use Linkedin.com”.  Now I love Linkedin.com and use it daily as a source of networking and keeping ahead of the industry, but let’s face it, when
a Linkedin.com user posts their entire career history and do not restrict
contact, they are hardly passive.  Even if they do restrict contact you know where they work.  Truth
is, Linkedin.com is one of the most fertile and accessible candidate resume
databases on the market.

Finally, why has bashing job boards almost become a national sport? Is it so difficult to accept that job boards have a place in every recruiting strategy and for the most part are simply the most efficient and
effective way for employers to advertise their openings to job-seekers?