Do you therefore see LightCloud as a possible alternative/complement to memcached? Certainly buying 500 GB of disk space is cheaper than buying 500 GB of RAM.
At Plurk.com we use both LightCloud and memcached. They complement each other. I.e. memcached is used for caching stuff - to reduce the load to MySQL. LightCloud is used to store persistent data - such as how many times a plurk has been read.
You could also store this in MySQL, but generally, storing key-value data is not the force of a relational database such as MySQL and LightCloud (and other key-value databases) are optimized for this kind of storage.
