ReligiousWars are long-running discussions (debates/arguments/FlameWars) in which there are merits to both sides (so there is never a clear winner) and participants have emotional investment in the issue (so participants are likely to resort to ad hominem attacks). When people who have 5 years of experience running one system attempt to have a discussion with others who have 5 years of experience running another system they are likely to generate much heat.

Some traditional ReligiousWars:

These are not mutually exclusive. Even the most long-running vi vs Emacs FlameWar will be broken off temporarily so its participants can engage in a Linux vs Windows FlameWar (on the side of Linux, of course).

Time does not settle all ReligiousWars. Some withstand age. The BetaMax vs VHS war is still going strong, despite not only BetaMax having effectively lost in the market (even though it was clearly superior), but both technologies being displaced by optical storage anyway. Others do fizzle out, such as the structured programming vs GoTo war, or the war over implementing systems in assembly language vs highlevel ProgrammingLanguages.

Some wars are so broadly and vaguely defined that different participants have different ideas about what the war is really about. Some people consider the Apple vs PC war to be about the AppleMacintosh vs MicrosoftCompatible hardware architectures (ignoring the fact that "Mac" has meant at least two entirely unalike hardware architectures during the brand's existence), so some of them would consider the war over. OTOH the majority of participants in this war are users with no expertise in programming or hardware architectures, who argue about an ill-defined derivative of user experience and/or interface/appliance design ethos – as much as they ever have.