[cyanydeez]

Open source licenses might be a spectrum but it's likely that the legal reality isn't. Like the famous double split experiment there's probably no spectrum and only a couple of buckets of legal validity.

[pnpnp]

As far as the buckets go, I still believe there is a pretty large spectrum.

BSD vs GPL vs LGPL are pretty dramatically different, and there are many in-between that might satisfy the definition of “open-source” at face value.