He points out that that they either didn't exist, or weren't "in the air" when he wrote the diary. Algorithm existed, for one example, but now it has a deeper,

He points out that that they either didn't exist, or weren't "in the air" when he wrote the diary. Algorithm existed, for one example, but now it has a deeper, sometimes darker connotation than it used to. That being said, it looks like he missed geocaching.