doom writes: "What's your favorite example of being burned by open source developers blowing off backwards compatibility? There seems to be an emerging trend of programmers dismissing legacy (and their user's expectations along with it). Needless to say, if all of the dozens (if not hundreds or thousands) of open source projects you rely on did this all at once, upgrading would become an exercise in pain not worth any number of feature additions, bugfixes or security patches... I theorize that the problem is ego, both too weak and too strong: "Hardly anyone uses this, who's going to care if we mess with it?" combined with "We're the guys doing the *work*, we know best!""
Some programming languages manage to absorb change, but withstand progress.
-- Epigrams in Programming, ACM SIGPLAN Sept. 1982