This study investigated the use of wikis for collaborative writing projects. Fourth- and sixth-semester German students wrote several of the regularly assigned essay topics during one semester in collaboration with another student using a wiki. Participants used a variety of strategies in the planning, writing and revision phases of their essays. They also achieved a very high success rate in correcting the formal mistakes they detected by pooling their knowledge about language issues. The students enjoyed working collaboratively as they could share ideas and work with each other's strengths, and they also liked the accessibility of the wiki. The wiki environment seems to benefit collaborative writing and promote successful revision behavior. (Contains 4 tables and 1 note.)