Why do you need a mobile website and why would you need an app?
The choice for an app or mobile website is highly dependent on the targeted audience and the purpose.
Keep in mind that your customer prefers a mobile website!
81% prefers a mobile site over an app
An App = a software program (application)
A Mobile website = website especially for all mobile phones & tablets
What is an App?
An app is short for application (program) and is a computer software program on a mobile device like a table or mobile phone. It allows you to perform specific tasks. Although Apps are often just called for the Apple app store Apps, it is just the proper name also for programs for the Android platform or the Nokia apps in the Ovi Store. Of course they rapidly lost it due to the transition of Nokia to Windows over Symbian.
There are mobile Apps available for all well-known companies like Amazon, Skype, Whatsapp, Facebook, Youtube and many others and are designed especially to make use on a mobile device more easy. Some Apps are totally useless but so much fun and therefor downloaded massively. Most mobile Apps are free or cost as little as $0,99.
An App is a software program, making it easy to quickly get a quote for a loan or search for a cheap, last minute flight. You know the name of the company, you know their website and you use their app.
What is a mobile website?
A mobile site is especially designed for the smaller handheld display and touch-screen interface. They have mobile-specific features such as click-to-call (to dial a phone number) or location-based mapping. You are presented a mobile version of the website after searching on Google.mobi or if someone visits your PC website with a mobile device. An App is a software program that you need to download. And this is the advantage over an app.
Mobile websites work in all mobile browsers and you don't need to download or install anything. A mobile website will give your customers a great mobile experience.
People that search for a product or service with their mobile device will get a (local) search result.
Mobile phones, even smartphones, have a much smaller screen than a PC desktop computer. The result is that your website will look totally different, even if it is optimized for mobile use. The letters are small, it is difficult to navigate over the site so it will frustrate you. Some sites don't even work on a mobile device. Also the term "responsive design" doesn't work anymore because people expect something else of a mobile site. They use different features and behave differently. And they want what they are looking for immediately on their device, quickly.
So a mobile site is a separate version of a website containing different content and has a totally different look than the PC website version.
More background information and research
A great website knows when someone visits the desktop PC site with a mobile device and serves a different site (a mobile version) in stead of the normal desktop PC website. This creates a great user experience. So a functional mobile website can't be compared with an app.
Many people think that adding an icon on your mobile desktop is called an app. The icon is just a feature and it is also included in the SiteOnMobi mobile website.