I'm not super familiar with memcached, but either memcached on RAM "is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration", or memcached is talking to a persistent database (i.e., HDD) in the background. Because I can read posts on that blog that are over a year old.

The recent Blizzard case found that making a copy of something into RAM created a fixed copy of it, I believe.

Remember, intellectual property rights are all thought-crime laws. They don't have to make sense.