New technologies continue to change the face of the Web. That's been a fact since the beginning of the Internet. It hasn't slowed down.
One important trend is the rise of smartphones and other mobile platforms such as the iPad and its imitators. A small but increasing percentage of visitors are viewing websites on such devices. In some industries this is more than a small percentage, as with restaurants.
There are two big issues and one big opportunity that websites need to confront in dealing with this trend.
1. Many of these mobile devices don't support Flash. That means if you are doing anything with animation, you need to look at alternate solutions. HTML5 is the answer to this for video, but since not all browsers support HTML5 (notably Internet Explorer, even IE8, does not), devices need to detect and serve up the correct code for the browser someone is on. Automated solutions to this (so people don't have to hand-code it) are increasingly available so this will not be a big problem moving forward.
But there are no good replacements for Flash in some situations. So we'll have to see how that all shakes out.
2. These screens are smaller. Even the iPad screen is a bit smaller than all but a small percentage of regular computer monitors. The usual solution is to offer up a mobile version of a website. The difference can be as little as displaying a version of the site that fits on the smaller screen. There's also the potential of offering up a version fully tailored to the limits and capabilities (see next) of the mobile platforms.
3. The latest generation of iPhone and iPad software makes it so easy to go back and forth between applications and transfer data between them. This creates great opportunities. Using your smart phone to call the restaurant just by clicking on the phone number on their web page. Mapping directions, looking them up in Google Places or Yelp or any of several other services - social media becomes real for many more businesses when these capabilities are considered.
These are all minor issues for most businesses, when mobile platform usage overall remains at a few percent. But there are a substantial fraction - and increasing daily - of businesses where this all ranges in importance from "useful" to "critical".
For starters, you need to know how much this matters for you.