To prevent edit clashes you can do what [Shog9 said][1] (it was proposed several times before) or you can go with the locking strategy.

Possible implementation:  
When the *edit* link is clicked, a flag in the database is set, that this post is edited. Every click on the *edit* link has to query the database, if it is already set or not. You cannot edit as long as it is set and you are informed about that.

These two options are used by version control systems for years. I prefer Shog's suggestion so.


  [1]: http://meta.stackexchange.com/questions/46078/quick-edits-force-a-badly-formatted-post-to-wiki-within-minutes/46087#46087