How can MMOs design for both vets and newbies?

This morning’s Daily Grind question comes to us from Kickstarter donor Specus, who asks,

I’ve seen many games where new players have trouble joining a game that’s been out for a while because the noob zones are almost completely empty. How can we keep the veteran players engaged with the new players?

This is one of the core problems of the genre, and solving it apparently isn’t easy. My favorite is sidekicking; nullifying level barriers (or better yet, not having them to begin with) seems the smartest way to bridge the experience gap between old and new players and get them into the same content. Non-combat gameplay can get people mingling as well; every time a newbie sells a stack of copper ore to a veteran, they’re engaging with each other. And let’s not forget overt incentives: Asheron’s Call’s monarchy system and Star Wars Galaxies’ skill-training system directly rewarded veteran players for taking newbies under wing and building them up.

What’s the very best way to design a game so that newbies and veterans can intersect without being bored at one end of the spectrum and overwhelmed at the other?

TH

suppose eve online is the answer since the noobs can do whatever they choose to do and still contribute to their guilds or the economy.