Tlen -

"Tlen – bez niego ani rusz. A jednak tak często o nim zapominamy. Weź głęboki oddech!" (Oxygen – can't live without it. Yet we so often forget about it. Take a deep breath!)

in 2001. Created by the o2.pl group, Tlen.pl was an instant messaging service that became a formidable competitor to the dominant Gadu-Gadu. "Tlen – bez niego ani rusz