I think each ecosystem had a very different experience with memcached adoption. In Java it was really limiting to do in process cache, and that limitation hit a wall while memcached usage was starting to spread. I assume Rails and maybe Python had similar problems, because all of the papers about GC techniques up to about that point were talking about Java. They got a lot of good stuff first or second.

What’s common though is that hard drives were not getting faster, but network hardware was hitting its stride. Full bandwidth (port speed X port count) routers and multi NIC were recently ubiquitous.

I had just come off a carrier grade software project when memcached finally hit my radar, and we had only spec’ed 3-5 servers for the web tier. That was still enough local cache hit rate to keep us running relatively smoothly. Or at least once we got done being honorary QA members for F5. We had lots of problems on that project with data modeling and so we actually were using too much caching vs precalculation but that’s a different story.