And though all the usual explanations are certainly valid - a distinct lack of marketing, an inadequate personal network, no real skills or abilities - I've been wondering this week whether at least some of it is due to identity management and personal branding. Something prompted by thinking even more about Facebook. Let me explain.
Facebook has a very single-minded conception of identity. You only have one face to share with the world - one sense of who you are. You can vary the levels of access but the way you present yourself to your colleagues is the way your friends see you too. On the surface, this makes a lot of sense: it's neat and tidy, it's logical and it makes targeting and demographics easier to resolve.
Unfortunately, it's just not how people are. We present different versions of ourselves to the world all the time - looking, behaving, talking in different ways in different contexts. And part of the joy of the social web is the plethora of tools and channels available - some that encourage one type of being and sharing, some that work well for others.
It is, of course, possible, for someone to scour your whole online identity and discover contradictions, it's just a bit time-consuming. It would be like them interviewing you and then following you home and observing you for a few days. Possible, but unlikely. If your whole digital life's in one place, it gets a lot easier.
I have dabbled with some of these slightly split personalities myself, but I think I made a mistake long ago by shovelling both my personal and professional life together on my blog - the place most people encounter me online - making myself less employable every time I mused about fried food or shared about some home-brew design project.
I realised recently that I got much more work when I was wibbling on about brand paradigms on the blog, but much less recently when the professional has been swamped by the personal.
And that's one of the concerning aspects about Facebook - it encourages just that sort of compression, not allowing you any presentational wriggle room. It's a tremendous place but a singular one: like spending your whole life in one room. Or always wearing the same clothes - after a while, that will send you mad.
And, I suspect, eventually, this uni-focus will be part of Facebook's demise. The Facebook generation will, sooner or later, sneak off and find places to be themselves. In the meantime, if you fancy employing me, just remember I'm a top planner and not a fat fool who spends too much time in cafes.