Launches and Re-launches: It builds cover quickly and has high levels of viewing frequency making it an ideal choice for advertisers with a mass-appeal product or service.

Strategic Branding: Used on its own or in synergy with other media, powerfully branded outdoor can be used to strategically position a brand and build awareness.

Sales Promotion Support: Posters can display promotional
messages while reinforcing branding.

Direct Response: More and more advertisers are beginning to recognise the value of Outdoor as a Direct Response medium, particularly to support an increase in overall coverage or up-weight specific locations.

 
More Links:  
Why Outdoor Works?  
More Reasons - How Outdoor Can be Used?  
Creative Guidelines - What Makes Good Creative?