Why do people buy common shares which give them no voting rights as a shareholder?
Sure while company is minting money (or debt and marketshare) you can find a greater fool to offload your shares.
However when things turn the Zynga way, what recourse do you have with these no vote shares?
At least Bond holders and Preferred Shareholders have certain rights.
PS Then there are the Chinese stocks such as BABA where you do not even own the assets of the main company but I digress..