More and more searches are being made from smart phones. People are looking for services and products while they are out of the house and not sitting at a desk.
Websites built for desktop computers don’t work too well on small-screen devices as they generally need to be dragged around to locate a section and there’s too much content to fit easily. People usually don’t want to read as much, so pages work best if they are smaller and clearer with the main call to action displayed straight away.
A few relevent pages with the main service information and marketing message & a click-to-call button or easy way to contact you are often all that’s needed.
Local business particularly should have their website mobilised. Google are detecting if searches have a local intention and presenting Local results based on their Google+ Local pages. There is a much higher chance that people searching for a local product or service will be looking at the website on a smart-phone.
The best solution is for a website to auto-detect the device they display on and present a smaller template for mobiles. There are 2 techniques being used at present to do this. One is called a responsive design, where the template re-formats itself to the iPad or smart-phone dimensions. The other is to display a specific template for each device which is the way we generally construct mobile sites using the WordPress framework ( details here ).