Every other day I get asked "What's the best way to expose my SharePoint portal on a mobile?"
The truth is, there is no one size fits all solution.
There are however a set of technologies and techniques available to us now that allows us to tackle different scenarios. Out of the box mobile views in SharePoint, Responsive Design, Mobile Web Apps and even native apps are all options and are all equally valid solutions for specific requirements. I'll cover each in turn and attempt to bring some clarity to mobile access and SharePoint.
Out of The Box Mobile Views
Mobile views are simple to implement but basic in nature. If your requirement is to navigate around sites, lists and document libraries then this will work for you. You can also perform searches. Customization is possible but not as intuitive or fast as using a Framework solution.
A framework such as Mobile Entrée can provide a richer experience than the out of the box views and will normally provide an API to code against, making extensibility and customization of the functionality intuitive. They will normally operate on templates which allows for powerful front end customization.
Views can be made available for different devices, e.g. you might want a two column layout on a tablet, whereas on a phone you would want just one. Frameworks will make form building simpler and also presenting back graphs and tables often used in Business Intelligence easy and more cost effective to implement.
This is ideal when you are delivering content to users and want to maintain the look and feel of the site. The page essentially scales and adapts to the device resolution. Perfect for marketing sites, news portals, communications portals, etc. Not so great for forms or functional portals such as document management solutions.
Mobile Web Apps
Sometimes you have a requirement that is very specific and targeted at mobile users. An example of this is a person search feature. On a PC, a user may be happy enough using your people search, but on a mobile the results may be difficult to read.
Mobile web apps are perfect for this, cross-device compatible and targeted specifically at mobile -- you can really focus on the mobile experience. You would most likely use these outside the context of the portal as a spot solution. Your portal may provide the underlying service but your app is specific to mobile.
Native Device App
This isn't comprehensive or definitive by any means, but it does show that you need to think about how you target devices when considering opening your SharePoint portals to other devices.
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