This wordpress plugin is no longer in active maintenance.
This plugin was a convenient wrapper to integrate Memcached. The actual implementation can be found here: https://github.com/Automattic/wp-memcached/blob/master/object-cache.php
Even though it seemed to work well we experienced harmful network peaks in some situations. We are now using other caching and performance optimizations methods that seem to be more predictable to us. That's why we are not putting any maintainence work into this plugin anymore. Feel freen to fork.