The purpose of allowing PPs, was to make it cheaper, quicker and less cumbersome for "junior" companies with limited working capital to raise funds in their initial stages of development. PPs can only be vended to accredited investors, but only to few in number (something like 10-20, but don't quote me) each time and with selected individual investors having to subscribe/commit to at least a prescribed minimum $value. The securities commissions also impose restrictions with respect to hold periods, prices, etc. PPs, as we and NOT have discovered the hard way, can come with some serious risks attached. One has to identify these accredited investors and do one' s DD very carefully, or have it done for you, i.e. by the IBK's of this world for a fee.
A normal course issue, which I believe is the terminology, is more complicated and involves the very costly and time consuming preparation of a prospectus. Common shares are offered to the general public through a sponsor, usually a brokerage firm. However, it still does not prevent companies like Rosseau, Sprott, etc from accumulating substantial blocks of shares.
You take your chances.
geoprof