Hi Eric,
LAN simply means no WAN (or MAN) links, i.e. locally connected in the same data center. Without getting into a discussion about the differences between LAN/MAN/WAN, the statement here is is just that "Groups of replicated instances are designed to support clustering within a LAN connected single-datacenter environment". Link speed is only one aspect and as I'm sure you know there are many other performance and reliability characteristic differences. I didn't mention that JMS gets corrupt. Also, JMS isn't point-to-point. All Connection Servers get all JMS messages.
A multi-site View deployment design should be done in a way where a site failure or WAN link failure does not affect other View sites.
Mark
