New York--24/7 Media Inc., the online ad network and direct marketer, and USA.NET Inc., an e-messaging service, on Tuesday announced an agreement to market each other's products. Under the agreement, 24/7 will offer its clients USA.NET's various messaging services available via the Web. In return, USA.NET will offer existing and future USA.NET clients 24/7's e-mail marketing services. 24/7 has seen its share of difficulties lately. Its CFO resigned last week and the company announced earlier this month that it was laying off 100 employees.