Meanwhile, a number of retailers have begun to raise funds for victim relief or set up blodd drives.
On the West Coast, numerous agencies called employees and told them to stay home when initial reports of the bombings were broadcast and the extent of the attack was unclear.
"It hit as people were heading into work. No one could tell what was happening" and many employees would have had to cross main bridges to get into the office, said Harold Sogard, general manager, Omnicom Group's Goodby, Silverstein & Partners, San Francisco.
Today, agency executives held a meeting "to thank people for coming in," said Jeff Goodby, co-chairman.
At sibling shop TBWA/Chiat/Day, executives in the New York City office put out a notice to worldwide affiliates indicating all employees were accounted for. Executives at a number of offices were unaware the agency had moved from its Maiden Lane location to Midtown further away from the building's collapse.
Other offices tended to business then closed. Interpublic Group of Cos.' Foote, Cone & Belding's Seattle office, for example, implemented a plan to pull client Boeing's ads worldwide, as they do anytime there is an air disaster.
FCB's New York office, meanwhile, was closed today, as were Havas Advertising's Messner Vetere Berger McNamee Schmetterer/Euro RSCG and WPP Group's Ogilvy & Mather Worldwide.
In the retail arena, a number of major shopping centers, such as the Mall of America, were closed yesterday.
Retailers such as Sears, Roebuck & Co. and Albertson's Acme Markets, with 150 stores on the East Coast, did their part to aid victims of the Trade Center attack.
Sears, which kept its stores open, said it will be pulling advertising through Friday and will evaluate when it will go back on the air "on an daily basis," a spokeswoman said.
She also said Sears plans to donate a "minimum of $1 million" to a relief fund for bombing victims, and has initiated blood drives at its stores and other locations.
Publicis Groupe's Frankel is also starting a relief fund with a $10,000 donation for the American Red Cross relief efforts, according to a memo from CEO Jim Mack.
Staff writers Tobi Elkin and Kate MacArthur contributed to this report.