Multivendor / Multiseller capability
IMHO, Dcommerce seems to be the future for integrated Drupal Portal-E-Commerce.
Such mission poses a "commitment duty": Leveraging Drupal to a not-inferior level than Ubercart did.
Drupal 7 is very appropriate for organizations willing to give its members (in a lot of countries) the possibility of sale their self-made products. Little producers, artisans, craftmen, artists need to sale their products directly/through NGOs.
Not to mention Internet entrepreneurs and SME clusters
Without multi-vendor capabilities, DCommerce leave all this people with complicated options, such us Drupal + Magento (no-native integration) or "outerspace": Joomla + addons (IXXO, WebGenie, Mighty, etc.).
I hope this feature/s to be added soon.
Comments
"marketplace"
This is generally referred to as "marketplace" capability, and you'll find lots of references to it in the issue queue and the forum here. Not there yet though, but I'm sure you can expect it.