Since I was messing around post board outage anyway, I went ahead and enabled a feature for posting ranks on the boards. They are currently set as follows:
Rank Posts Required
S.H.I.E.L.D. Trainee 0
S.H.I.E.L.D. Technician 50
S.H.I.E.L.D. Field Agent 100
S.H.I.E.L.D. Special Agent 250
S.H.I.E.L.D. Spec-Ops Agent 500
S.H.I.E.L.D. Psi-Ops Agent 1000