I wonder if that's just emergent behavior.

It's possible that the first several postings along the lines of "Smart programmer wanted as co-founder for new social networking concept (that also shortens urls)", but it has since been noticed by recruiters as a "free job board" and thus is filled with "Programmer/Analyst III with J2EE" positions.

Perhaps they need to work on the tech a bit to discourage the job postings and encourage the actual entrepreneurial stuff.