Dive Brief: 

• The Interactive Advertising Bureau has released a public letter — along with publishers including AOL, The Wall Street Journal, Conde Nast, and Time Inc. — urging advertisers to design in the mobile-friendly HTML5. 
• The letter urges advertisers to insist their agencies design in HTML5 because it is the only "open, industry-standard, universal format for building mobile-ready creative."  
• Within the letter, IAB lists the resources it offers for learning HTML5, as well as announces an upcoming webinar series about HTML5. 

Dive Insight:

IAB certainly has the right idea about the importance of integrating mobile into an overall advertising campaign. Because it is the industry standard at the moment, HTML5 is the best avenue for ensuring ad creative will appear correctly across all screens. Advertisers and agencies would be wise to listen to IAB's advice.