I can see how this could be confusing so I'll try to clarify it a bit in hopefully understandable terms. (Disclaimer: Contains generalisation, simplification and cutting corners. If there are glaring mistakes, feel free to correct.)

1. There is Nokia Maemo 5 / Fremantle now. The next release would have been Nokia Maemo 6 / Harmattan. Now, it is called Meego / Harmattan instead, but it's still the same Harmattan that it was going to be. This would be way clearer if they didn't rebrand it as MeeGo yet, but they wanted to get the marketing behind that brand already. You can think of Harmattan as half MeeGo. The next release after Harmattan will be Nokia's first full MeeGo.

2. You need to understand the layers, which together form an operating system. It may be difficult if you come from Windows/OS X world because they both only have one user interface. UI and applications, however are only the top of the OS pyramid. Underneath them there are a lot of stuff that actually make it all tick. That's what Meego is about, providing a common base for user interfaces and applications to be built on. When you think of Meego in general, think of everything you as an end user don't see.

3. What you actually see, the UI, applications, services etc. can and will vary depending on who made the Meego device. LG's UI may look totally different from Nokia UI. You'll only see Ovi applications and services on Nokia devices. These manufacturer specific applications on top of Meego won't necessarily be open source either. But the base on which they are built on is the same.

If you keep all this in mind, the discussion hopefully makes a bit more sense.