Perhaps because of my long history with Unix, DEC VAX and RSX servers, and high-reliability industrial control systems, I still define "continuous operation" only in terms of "no interruptions of service", and I'm pretty hardline -- for example, restarting Apache to pick up a config file change can be done gracefully and inperceptibly, but it is an interruption of service if anyone's download gets stepped on.
A reboot is an interruption of service lasting typically a few minutes, between the start of service shutdowns and the time when all services are up again. But perhaps more importantly, a reboot reinitializes the system structures, clears caches, all sorts of refreshing cleanup occurs. The test of long-term system stability is whether it keeps going without that refreshment -- that proves there aren't any slow memory leaks, tables that don't have enough space and fill up, etc.
I know I'm being picky here, but my background taught me that counting "continuous operation" and ignoring reboots is just as, ummm, incorrect as counting "continuous fasting" and ignoring snacks. Fasting is fatal; anything less is not fasting, it's partial fasting. The reason RAIDs in HA systems are designed with hot-swap spares is exactly because in some systems any interruption is intolerable. For the smaller computers most of us work with, a reboot is actually a breather. :)
That said, I certainly acknowledge the validity of your description and achievement.
Like being a little bit pregnant. . . but we were discussing operating without crashing. . . and I was quite specific to include downtime due to updates.
I notice that our fellow with the 18 XP computers controlling his process network hasn’t come back to answer my questions. . .