[danprager]

An app store gives somewhere for vendors to hang up their shingle (like a mall), and -- depending on the barriers to entry -- gives some assurance to "shoppers" looking for apps.

We've just launched a new business app, bSelling - http://bcisive.austhink.com/solutions/bselling, on Salesforce.com's App Exchange for add-ons to Salesforce CRM, and wish that there were more such stores.

It's actually a bit like the Microsoft stranglehold on the old PC software market; there were certainly negative aspects, but the standardization effect was certainly market-making.