I was wondering if the argument for providing all the content from your desktop site on your mobile site includes making all the functionality and features also available?
This is a difficult one to answer but there quite a few myths out there. For example the previous answer says...
"For example, you may want people to use the mobile site to view all the products, but not necessarily to purchase or rate/review the products."
This is based upon the idea that people browse products but don't go through the whole checkout process on a mobile. Having built a mobile website for a retail store the evidence was that people DID want to buy on their mobile, providing it was easy enough. And even for those that went thought the whole process there was significant sales to mean the functionality should stay in.
It is true that different modes of activity are more prevalent but many users are frustrated that the mobile version of the site is better designed but often misses out key functionality - for example buying on an ecommerce site.
A well thought through responsive site can deliver on the needs of all the users but there are still pluses and minuses to that approach. Also keep in mind mobile devices no longer mean a mobile phone used on a train, for example, but also includes someone on their ipad in a cafe or on their notepad sized device at home.
Giving everything to everyone and providing a clear, simple and effective user experience should be your goal. Redesigning for other devices will nearly always bring up better ways of doing things that can be reincorporated with the main site. Compared ebay's mobile offerings and their main site and you can see many ideas that should be on the main site - such as the ease of accessing watch-lists.
Splitting up functionality is often done for ease of building and getting things out there rather than for user experience reasons.
Yes and No.
There is a a lot of analysis you would need to do before you move everything from your desktop site to mobile site.
The internet of things is moving towards Mobile/Tablets etc. Talking a little into the premise of the argument presented in your question, that argument is brought up because the screen size of the mobile is small compared to the desktop and hence it is said that even though the design is different (because of difference is size of screen/resolution), the content should be the same.
That being said, for website's that provide functionality/features- you never know what features a customer might want to use from his mobile. For example, a desktop website might allow me to view a preview of each item in a list when I hover my mouse over it. This functionality obviously cannot be the same in mobile, however I might want to use this feature in the mobile website, probably by some other mechanism.
The idea here is to reform your mobile design website while keeping the content and functionality same. The mechanism to provide that content and functionality can be poles apart, however it just shouldn't compromise on your user experience. THAT is what a great mobile site design.
Also, if you think that some content is irrelevant for the mobile website, double check it. Use google analytics or any other such software to make sure that your desktop site doesn't get much hits on that page/feature. Because IF they do, then you can't ignore the possibility of them being wanted to be accessed on a mobile device as well.
In summary, yes the functionality and features are important to be replicated in the mobile site. No, they don't need to be (rather they shouldn't be) in the same design framework as the desktop site.
Check out Flickr's mobile website. They do an awesome job of providing features and functionality available on their desktop website and replicating it to their mobile website. Not that I fully support all of their design choices, but they are definitely in the right direction.
If the site is designed well enough, then there is a good separation of the content from the functionality of the website and therefore it may make sense to not include all the functionality and features even if you make all the content available. For example, you may want people to use the mobile site to view all the products, but not necessarily to purchase or rate/review the products.
In designing for both desktop and mobile, it is very important to consider consumer behaviour and your customer experience. If you provide users with the convenience of a mobile site but a suboptimal experience, it might detract from the rest of your website/brand/image. There are various strategies for responsive design if you are building a website from the ground up, but it does require more consideration about the content of your website as well as the users.
No and no. Content != Functionality.
In this case not even all functionality is applicable to both platforms. For example, a desktop site might benefit from keyboard shortcuts or a detailed navigation sidebar which are not applicable on a mobile device. Similarly, a mobile device might incorporate location awareness, "get directions", or the ability to place a call instantly which may not be appropriate on a desktop site.
So not only is content categorically different than functionality, you may need to offer functionality on the mobile version that doesn't exist on the desktop version.