I know many of you have found plenty of Bobbleheads in Fallout 4 on your own, but to find all 20 of them can be a bit frustrating. The idea of the bobbleheads being a piece of exclusive Vault-Tec merchandise is supported by a computer terminal found within Vault-Tec HQ, in Fallout 3. The computer provides a list of 'orderable' merchandise such as clothing and Lunchboxes, but when a bobblehead is requested the terminal reports that they are only available to executive staff.
As in Fallout 3, in Fallout 4, each bobblehead increases a corresponding S.P.E.C.I.A.L. stat permanently by one. Bobbleheads that previously increased a skill, now grant a permanent unique perk. Taking a bobblehead while your stat is at 10 allows that stat to increase to 11.