Semantic HTML means using HTML tags for their implied meaning, rather than just using (meaningless) div and span tags for absolutely everything. Why would you want to do this? Depending on the tag, the content in the tag can be interpreted in a certain way. Here are some examples.

Header tags

If you use <h1> instead of <div class="header">, and <h2> instead of <div class="subheader">, et cetera, Google and other search engines will interpret your headers as being important titles in your page. This way, when people search on the words in your headers and sub-headers, your page will be considered more relevant (and rank higher). Plus, it's much shorter and cleaner.

This works both ways: don't use header tags for anything except headers, especially not increasing your font size or outlining your search engine keywords. This way, your page can be parsed for structure (you can do this with the W3C HTML Validator). This structure can then be used by screen readers or other tools to build a table of contents for your page.

Form labels

The <label> tag is so sadly forgotten. It's not immediately clear what the point of using it is, so very few web pages take advantage of it. The label tag is used to identify a label for an input field, for example "E-mail Address". It can either be used be wrapping it around the text and input field like: <label>First Name: <input name="fname"/></label>, or it can be used with the for attribute like so: <label for="fname">First Name:</label> <input id="fname" name="fname"/>.

Why use the label tag instead of <div class="label">? Well, it's shorter and cleaner. But it also let's screen readers and other tools identify the text associated with an input field. Without using the label tag, it can be very difficult for some people to know what is supposed to go into your form fields.

Tables

These days, everyone's moving away from using tables. This is great because tables aren't intended for structuring the way your web page looks. But tables still have a very important purpose. Any time you need to display data that would go in a spreadsheet, tables are here to help.

When using tables, there are a number of tags and attributes that aren't widely used, but are very important for accessibility. Use the summary attribute to give a longer summary of the data in the table. Use the <caption> tag to give a brief title to the data. Use <th> tags to identify the column and row headers in your table. Then, you may want to use the headers attribute on the <td> tags to identify which headers apply to that cell. For more examples and details on accessibility with tables, see the W3C's Accessibility Guidelines.

Lists

Lists are the new tables. Whereas tables are intended for grids of data, lists are intended for lists of content. This is great for us, because most web pages are essentially lists of different things. For example, look at this site. On the front page, I have a list of blog entries in the centre. On the sides, I have lists of links (archive, categories, et cetera), and the sides themselves are lists of lists. If I had used tables, I would've been saying "this stuff on the left has something to do with the stuff in the middle", but it doesn't, really. By using lists, I'm simply saying "this stuff is a list of items that have something to do with each other", which they do.

You have three types of lists to choose from, but choose wisely. There are Ordered Lists (<ol>), Unordered Lists (<ul>), and Definition Lists (<dl>). Only use Ordered Lists when the entries have some kind of order. Only use Definition Lists for definitions (eg. for a glossary). Use Definition Lists any time you need name/value pairs, or when you need to break your list up into sections. The rest of the time, Unordered Lists are a safe bet.

Lists not only give structure to your page, they're incredible handy for styling. You can just put an id or class on the outer tag (eg. <ul>), then style both the outer tag, and the inner <li> tags.

Conclusion

Try to use the full variety of HTML tags whenever possible. Sometimes you'll be stuck with using <div> tags, but try to limit them to whenever you can't find a suitable HTML equivalent. At the same time, try to avoid using HTML tags for anything except their intended purpose. By doing this, your HTML will be cleaner, and its structure will be more readable and understandable -- not just to people but to screen readers, search engines, and other programs and tools.

As I've said before, and I'll say again, the last thing the web needs is Buzzword Hell. All buzzwords do is distract from the real tangible ways we can improve the web. So now, I introduce a way you can help save the world from Web 2.0 buzzwords!

Buzzword Hellfire

I just had a look at the WayBack machine for thefutureoftheweb.com. Turns out someone else had it before. Creepy.

Have you ever wanted to prevent a JavaScript event from firing when it has been bubbled up from a child element? For example, let's say you have an onMouseOver event for a parent element. Anytime the mouse moves over any of the children elements, the parent's onMouseOver event will keep firing. Or, let's say you have an onMouseDown event on a parent and another on its child. Both onMouseDown events will fire when someone clicks the child. Sometimes this can be a real pain.

Anyway, enough examples, let's look at a way to avoid this. We need a way to fire an event only when the element with the event handler is the target element of the event. Here's the solution event handler:

function eventHandler(e) {
     e = e || window.event;
     var target = e.srcElement || e.target;
     if (target != this) return;
     
     // the rest of the function
}

Simple enough, once we have the code. Let's look at what it does.

First, we find the event object. In Firefox and Safari, it's a parameter to the function. In Internet Explorer, it's in window.event.

Having that, we need to find the target in the event object. This is the first element the event fires on, the inner-most or top-most element. In Safari and Firefox, it's target, but in Internet Explorer it's srcElement.

Finally, we will compare against the element the event is attached to. The element the event handler is attached to can be accessed easily with the this variable.

For more information on event handlers, I highly recommend the excellent resources at QuirksMode:

• Events order (event bubbling vs. capturing)
• Event Properties
• Event compatibility tables

Update: you need to do a little bit more if you are dealing with mouseout events. If you move the mouse into a child, this triggers the mouseout event on the parent. In this case, the target will match the parent. So, you'll also have to get the 'related' element (the child) and make sure the target isn't one of the ancestors. Here is the updated function for mouseout events:

function mouseOutEventHandler(e) {
     e = e || window.event;
     var target = e.srcElement || e.target;
     if (target != this) return;

     var related = e.relatedTarget || e.toElement;
     while (related != this && related.nodeName != 'BODY')
          related = related.parentNode;
     if (related == this) return;
   
     // the rest of the function
}

Special thanks to QuirksMode's Mouse Events page for helping me figure out that one!

I know, this question has been answered thousands of times. Even still, nobody can agree on what it is exactly. Here's my take.

Web 2.0 obviously implies the "next version" of the web. Ask Tim O'Reilly (who coined the term to promote a conference), and he won't really be able to summarize it either. He'd rather define it by example. DoubleClick is Web 1.0, Google Adsense is Web 2.0. Personal websites are Web 1.0, blogs are Web 2.0. Content Management Systems were Web 1.0, wikis are Web 2.0.

Web 2.0 is said to include everything from tagging, Ruby on Rails, AJAX, peer-to-peer, RSS, the perpetual Beta, and user-contributed data. Let me propose this: Web 2.0 includes anything that was done successfully on the web in 2005. There, I've said it. Now, I'd like to propose something else: Let's focus on the different ways the web has improved, and let's never use the term Web 2.0 again. Seriously, starting right now. Who's with me?

Having said all this, the many different definitions can finally be read without that nauseous feeling. Don't worry any longer that your website is running the wrong version of the Internet, just relax and take a look at how far we've come. It's not worth much to say "This website follows the new trends in web sites, this one doesn't". There's certainly no need to start a new industry over it. Instead, let's just see what works and what doesn't.

If we spend all our time defining such a vague marketing term, we're going to severely miss the point. There is no Web 3.0, and there needn't be a Bubble 2.0. We have a lot of really great examples to follow, and there's still a lot that hasn't been done. So let's just keep doing what we do best.

So let's see what we can do with Folksonomies, let's find things every web site can learn from blogs, and let's see what new directions we can go in in the future of the web.