The following titles are the original and ports/expansions of the same game:

* Phantasy Star Online

* Phantasy Star Online ver. 2 (expansion--note this is different than Phantasy Star Online 2 which is a different game and should be separate)

* Phantasy Star Online Episode I & II (port + expansion)

* Phantasy Star Online Episode I & II Plus (essentially just a patch!)

* Phantasy Star Online: Blue Burst (port + expansion)

I and a few other PSO streamers realized how many fellow streamers of this game we were never aware of because there are streams in each of these categories, so combining them seems like a good idea so that our little community doesn't have to follow 5 versions. I believe other games (such as Pokémon flavors in the same generation, StarCraft II, etc.) have been combined before.