I assume the GP meant something similar to restricted stock, where you are severely limited in selling and transferring of your stock until certain preconditions are met (change of ownership, IPO, etc).
Privately-held stock, i.e. restricted stock of non-reporting companies, can't be sold "to the public" and generally must held for at least one year [1], but other than that is quite transferable pre-IPO. That minimum holding time can vary, too, depending on circumstances. Most transfer restrictions are put in place by companies, not law.
It's not legal to go out and raise a bunch of money from unaccredited investors. Companies will most likely have to get approved for Regulation A+ by the SEC before Indiegogo agrees to sell ownership, in which case the shares are transferable once the offering is closed.
