If your in business; any business, you need a Mobile version of your website.
To differentiate between a mobile APP and a Mobile Website, you need to understand the functions of each. A mobile APP is an application specifically designed for a type of device such as an iPhone or Android. If designing an APP, you will need to design separate apps for each device. APPS are downloaded by the user to the users device and installed. A mobile website is a mobile version of your website that is designed to display on 99% of all smart phone devices. It is your website on 'Mobile Steroids' and can mimic the feel of a mobile app with many of the mobile app features present. , the CALL US button on every page.
With 70% or greater of users now using their mobile device to search for products, businesses, local services, etc, it's always-so important that you present yourself in the best way possible. Rather than a shrunken down version of your website that requires zooming in and out to read and function.
Real estate is a good example of how mobile website comes into play. People are driving around looking at property and will be using their mobile device. If they search Google and find your site, you want them to see your mobile version that displays your site beautifully and functionally on all devices. The idea here is to have a auto-redirect from your website so even if they see your sign, an add in your local real estate magazines, etc., you can advertise only your main URL. The auto-redirect will determine the device and display your mobile website.
I can show you a good example of this in use. http://mypelicanrealestate.com is a real estate website that has the auto-redirect built in. Take a look on your desktop and then on your smart phone. Same URL. Designed using JQUERY Mobile.
JQUERY mobile is a lightweight framework (FREE) that allows you to create mobile websites using a select set of tools. Truly a cross platform HTML5 Framework.
JQUERY is a free download and comes with quite a bit of tutorials and instructions.
If real estate is your business, it gets a bit more complicated as you will want to add IDX for mobile so users can search local property listings.