Advertising for an event of any kind, whether it is a sale, nightclub party, art showing or even non-profit auction, requires quickly communicating pertinent details. Unlike brochures or booklets, flyers are meant to be scanned quickly. After the information has been received, the flyer is either saved or thrown away, so marketers only have a short amount of time to convey what's essential. Some events require more information than others, so an organization's choice of flyers can vary because of this.
A 4.5 x 11 flyer has a distinctive, narrow shape that makes it stand out. There isn't a tremendous amount of room on it, but invitations and announcements printed on one of these items will be bold and to the point. Names, dates, locations and a few images may be all that's necessary for a one-night event at a restaurant or bar.
Using a 1/2 page flyer will convey slightly more information. There is a bit of additional room for directions and perhaps even space to list various artists who may be playing at a concert.
Full page flyers should be reserved for events that require a lot of detail. Charitable organizations with many sponsors may wish to select this type, as would art galleries that want to offer samples of the works that will be shown.