Groupon named in class action regarding expiration of discounts.  The complaint alleges that the expiration dates the company places on its discounts are illegal. The lawsuit alleges Groupon and its retail partners issue the deals knowing many customers won't use them in the allotted time and that federal and state laws prohibit the sale of gift certificates with expiration dates.  The lawsuit asks for unspecified damages, including full refunds, and a court order preventing Groupon from issuing discounts with expiration dates.