Media giant WPP has entered into an agreement to buy a stake in Myanmar-based advertising agency, Today Advertising.The company, based in Yangon, employs 60 people, and WPP's investment continues its strategy of "developing its services in fast-growing and important markets and sectors," the group said today.With this acquisition, the number of countries in which WPP operates has increased to 108. The firm, led by frontman Sir Martin Sorrell, did not disclose the size of the stake, or any financial details associated with it.Today Advertising will be incorporated into WPP's Asia Pacific region division, which generates a quarter of the group's revenues per annum and employs around 42,000 people.BC