The time when users are getting smarter and demanding, its always good to have their feedback or let me report any bugs they find in the application. And a good percentage of users are pretty tech savvy and would love to commend about the product and their user experience.
For any B-to-C product, I would always vote for having a simple way to get user reviews; this would serve as both – getting to know what user wants and having a user testing done and knowing the bugs one might have missed.
I see the same being incorporated in Gmail and Facebook android apps. And I think it will be a good idea to have them in LinkedIn, Twitter apps. Like, I have have other posts which comment on LinkedIn android app and I would have been happy to give some feedback or report a bug about their App.
Moreover, I see no harm in having a feedback/ report-bug as another menu item in eCommerce apps like Macys, Walmart which can be improved or can gather some user thoughts. And I would also prefer to see this (usre voice) somewhere as a part of web-app as well. Like we have in TechCrunch, where they ask for a tip/ comment in the top right section on the home page.