It's quite simple. Each post, the poster must make a paragraph that makes some sort of sense using only words beggining with the corresponding letter of the alphabet, for example: The first post starts with A, the second post starts with B, so on, so forth.

I'll start:

A antelope and an animated anarchist anticipated ants antagonizing a aristocratic alleyway. Afterwards, alleyways and aristocrats along Afghanistan ate arrogant armour and addicted a armoury. Also, Allen ascended alps: an area at arresting altitude.