It means you don't get a board seat, and you probably get common, non-voting stock.

Sadly, it probably comes WITHOUT an anti-dilution clause, meaning that any new stock allocated will dilute your 5%. As a company progresses through its capitalization phases, new stock is likely to be allocated, usually in new classes that offer more protection to the investors, and less protection to the "monkeys" like us.

Your "5%" will likely be converted to a number of shares at the time it is executed, and that number of shares will likely NOT be 5% of the total number of shares available when a liquidation event (IPO/Buyout) occurs.