Currently, Wikis are the most popular form of collaborative editors. Recently, some researches have proposed fully decentralized wikis relying on peer-to-peer networks. This new architecture subtly changes the behavior of wiki in case of concurrent changes. While traditional wikis ensure that all pages have been reviewed by a user, some pages in a P2P wiki are produced by the system through a automatic merge. To overcome this problem, this paper introduces concurrency awareness, a mechanism that makes users aware about the status of wiki pages. The particular context of a P2P wiki system makes traditional awareness mechanisms inadequate and requires the desgin of a new one.