The agency's revenues have tripled in the past year, to an estimated $5.2 million to $7.5 million.
"We're going to have to stumble hard not to double that again this year," said General Partner G.M. O'Connell.
Modem, founded in 1987 with two employees, is adding 15 to 20 staffers to its current base of 33, filling positions in media (including a media department chief), creative, multimedia production and account management.
Modem is also hiring an executive to lead a new division that will license interactive marketing tools developed by the agency.
Driving the agency's hiring binge are several new projects from existing clients, including Coors Brewing Co., AT&T, J.C. Penney Co. and CBS. The projects range from ongoing Internet advertising (Modem designed the Zima home page and AT&T's HotWired sponsorship) to new online and multimedia work.
Modem expects to add a financial services client by month's end. The agency is also pursuing accounts in the auto and microprocessor categories.
Mr. O'Connell said he's entertained acquisition overtures from media companies and ad agencies in recent months, but the agency will remain independent for now.
"We've talked to people, but nothing interesting has come our way," he said.