From the Star Alliance Website:

Star Alliance Gold Benefits
Priority Reservations Waitlisting1 - when there aren't any seats left on your preferred flight, gives you priority should a seat become available.
Priority Airport Standby - gives you top priority when standing-by a flight at the airport.1
Priority Airport Check-in - allows you to check-in at the Business and/or First Class counter
Priority Baggage Handling - like you, your bags get priority treatment and are among the first to be unloaded.
Extra Baggage Allowance - an additional 20kg (44 pounds) or one additional piece of luggage2 which means you can check in three bags instead of two.
Priority Boarding3 - enjoy the freedom of boarding at your convenience along with First and Business Class passengers.
Airport Lounge Access - available worldwide for you and a friend4 when you travel with any Star Alliance member airline, regardless of your class of travel.

http://www.staralliance.com/en/benef...silver-status/