I am currently in the process of developing a website as a personal project. Normally I am quick to adopt new technologies, even though IE makes it a pain sometimes. However, this one makes me worried because the adoption rate for current browsers is spotty even in cutting edge ones like Firefox, Opera, and Safari.
Would you consider adopting HTML 5 / CSS 3 for your website, and why? Can you list any non-obvious drawbacks to adopting these new technologies?
I will consider using HTML5 / CSS3 when the time is right. It is not yet.
The answer to why consists of two parts:
Technically, the browsers are still playing catch up. The support is not yet mainstream across all major browsers.
Humanly, the adoption of a new browser wave takes millennia. Even today many people are reporting from their site statistics that a bigger portion of users coming with IE6 and IE5 oboard. Even IE7 has not been widely adopted yet. And we already need IE8. And you're talking about some IEn whenever this will happen.
As a sort of a vicious circle, since there is no widespread support for HTML5 / CSS3 yet, developers are not targeting these standards, consequently, the browser makers do not get a stream of feedback they absolutely need to fix bugs and improve support in their products. Understanding this, developers are not fond going with it yet. So both parties are waiting for each other. And the users, oh well, they do not even know what HTML or a browser is (this little blue or orange Internet on my taskbar).
I use CSS3 to enhance my website for users who use a proper browser but I still make it completely usable for the others.
The obvious drawbacks (Spec still being fought upon, adoption rate extremely slow) looks like real deal-breakers if you develop a site that will actually be used.
That being said, if you're just "toying around" I'd certainly give html5/CSS3 a try, since most of it seems pretty exciting :)
I can't think of any drawbacks except for the glaringly obvious: they're not widely implemented, yet. If your personal site is required to be useful to the IE6 viewing public then there's enough problems with css 2.1 without looking to complicate things with css 3.
As for html5 I've -and this is personal, and based on experiences a few months old now- not found it to be either implemented well enough to offer anything resembling a reward, or any ease of use that isn't already available -admittedly with jQuery, and the use of ids instead of elements (<div id="header"> instead of <header>)- in html 4.1/xhtml1.1.
While waiting for IE to catch up isn't likely to be entirely sensible, I think -for general use, and your personal website may be exempt from this- it's probably wise to wait for sufficient implementation in the majority of browsers that feature degradation and fallback is the exception, rather than the rule. Personally, when FF, Chrome and Opera have good implementations that's when I'll start using html5.
If your site brings new features as a result of using CSS3, then users who have a modern browser will get those extra visual benefits and others with an older browser don't, its not that much of a big deal. So there's no text-shadow in IE, so what?
A small percentage of people in a high traffic website can equal a few thousand people or more even if its 2%. And that's something significant. Small, but significant.
Remember, 2% of users today will be 100% of users tomorrow. There is no where else to go, eventually all browsers will support CSS3 so adopt new standards and future proof your code.