Note to franky - SegWit is a backwards compatible protocol upgrade.
Do you even know what that means?
Yes.
For the ordinary user, SegWit is backwards compatible. It needs a majority of the hashrate to avoid a chain split, but by default it doesn't cause one (as I understand it). Therefore it would be an upgrade of Bitcoin with a consensus, and if in the future there was a split that separates from consensus that was agreed before, that one would be the "new coin" to put it that way.
Feel free to correct me on that but I'm pretty sure that I can call it backwards compatible.
You are correct -- however: Proposals like BitcoinXT, which require a majority of hashrate to activate, ALSO do the same thing, even though it is a hard fork... yet we still had plenty of shills/idiots trying to label it an "altcoin".