What Is The Formula In Making A Long-Standing MMO?

There are various different aspects that affect the longevity of an MMO and when it's date with imminent death is. These include:

- The game becomes stale (same old stuff, just remade in a slightly different way)
- No user support or very little
- Playerbase never takes off so it doesn't last outside of a year
- Competition
- No unique selling point

Take a look at the below article which tells us more about what Guild Wars 2 is planning to do going forward to try and maintain their playerbase. The factors they discuss are fairly common sense, however, even with the best laid plans it may still prove futile.

http://uk.ign.com/articles/2013/03/07/how-guild-wars-2-plans-to-survive

This is because the MMO genre can be very fickle, purely because there are so many options available. It's very easy to be able to move onto different adventures.

So what makes an MMO stick? What do you love about your favourite MMO that means you aren't easily deferred onto something else?