I've noticed a lot of web designers are touting a 'mobile website' as an up-sell or separate service.
I think this is not only damaging the customer's online presence but also reflects badly on the web design industry itself.
I'm referring specifically to a separate mobile website that is built alongside your current website and requires it's own content, and therefore it's own administration. This is clearly a bad idea. You'll need to update your content in two places and more significantly your clients will experience a cut-down version of your original site.
I think the reason business are pushing this as a service is because a separate mobile site is quick and cheap to build. It only needs to work on mobiles, will contain very little content, and always has the desktop site as fallback for any inadequacies.
The answer is by using a 'responsive design'. This is a new technique used by the best web developers to create websites that work perfectly on all devices, including mobiles, tablets and desktops.
The brilliant thing about a responsive website is the mobile visitors to your site see the exact same content as your desktop site. All your content is gracefully reformatted and optimised for display on small screens.
If you're using a CMS like SetSeed to manage your content, you only need to change it once and visitors on any device will see your latest version.
The problem with responsive designs is they are fairly complex to build and execute well. More importantly, if you've had a website built recently, you might need to have certain parts of it altered to allow it to become responsive. If your original developer isn't willing to do this, another developer might prefer to start from scratch rather than working with your existing site.
This, understandably, is going to result in a reluctance for people to upgrade their websites to become responsive and, even worse, consider adding a cheap separate mobile site instead.
In summary: If you're looking to buy a new website now, make sure you specify it to be built using responsive techniques, and be prepared to pay a bit more for it. Rest assured it will be a wise investment. Mobile and tablet browsing is only going to get more prevalent. If you've recently had non-responsive website built, prepare to pay for a responsive rebuild and don't spend money on a separate mobile version - it's just false economy.