I dislike the comparison to IE6 because it's easily shot down with the many ways in which the situation is different. But Safari absolutely is falling behind other browsers in API support and could well end up holding the web back. Particularly on mobile, given that iPhone users are not able to install a different browser runtime.

    I dislike the comparison to IE6 because it's easily shot down with
    the many ways in which the situation is different.

Inseparable from an OS version and falling behind the state of the art.

What else is there?

Being pretty disingenuous to compare IE6 with WebKit in terms of implemented features. Many websites had to be specifically coded for IE as it wouldn't render correctly many basic parts of HTML/CSS. WebKit is deficient mainly in the newer, less popular features.

Also Microsoft would unilaterally add proprietary features and tie their software to it e.g. Outlook/Sharepoint which then encouraged corporations to do the same as well. Apple actively participates in standards organisations eg. one for Web Components:

http://www.w3.org/2015/04/24-webapps-minutes.html

Legitimate questions:

    Many websites had to be specifically coded for IE as it wouldn't render correctly many basic parts of HTML/CSS.

Was IE6 demonstrably less compliant than other contemporary browsers? I recall - similarly - sites that were "Best viewed in Netscape Navigator at foo x bar resolution."

    Also Microsoft would unilaterally add proprietary features

IIRC, IE6 added XmlHttpRequest, which - though there were other workarounds to accomplish the same thing - enabled AJAX.

Do not other browsers even today add their own features (e.g. browser-prefixed CSS properties) prior to standardization?

    ...and tie their software to it e.g. Outlook/Sharepoint

Okay, that's definitely bad.

Falling behind was never IEs worst 'feature'. Standards compliance, security and speed were much bigger issues.

    Standards compliance, security and speed were much bigger issues.

In these respects, how did it compare to other contemporary browsers?

When it was released? It was the best (ok IE5 on Mac may disagree). Seven years later (when IE7 finally appeared) it was worst.

Initially well, but soon very poorly, because IE6 remained a contemporary browser for an unusually long time.

Distilled down to the core, the fundamental problem with IE6 was the five year chasm where development was completely stalled. When the version was finally bumped in 2006, so much time had elapsed that the solution was unsatisfying for everyone: changes so major that compatibility was problematic, but still insufficient to bring it up to speed with its competitors.

Safari may not be implementing bleeding-edge features at the same rate, but at least the engine is being continually developed and improved.

  > But Safari absolutely is falling behind other browsers in
  > API support and could well end up holding the web back

I am afraid that hastily releasing half-baked APIs and moving on to the new shiny things will do web more harm in the long run. IMHO web is suffering a huge identity crisis right now.

IMHO the problem is their yearly release cycle. Right now the feature might be too incomplete to include, which is fair. But in a few months it would be, but its still 10 months at minimum before Safari adds support for it.

Can you cite some examples?

That would be a very distant possibility. Chrome is indeed being used by a lot of Apple users however, the loyalty and fan base of any and all Apple products is too big and, pardon me, egoistic. They would not let it go that easy

Curious where this is coming from.

Safari doesn't lag that far behind WebKit and iOS/OSX both have very frequent update cycles. And has WebKit really been that bad at adopting internet standards ?

Sadly yes. While it's not really as horrible as many people (myself included) have said, the problem is their release cycle, and iOS's lock in.

One a year means that it will probably be 2 years before any new features are "stable". (for example IndexedDB support came out and it was so buggy that it was unusable, it wasn't until ios8 that it was even somewhat usable, and it still has several game-breaking bugs)

So you run into problems like this where in 6 months every other major browser will have stable shadow DOM support, and safari will still be at least 6 months away from its first (possibly buggy) release, meaning there could be another 12 month wait after that to get a good implementation. And while any other platform can install an alternative iOS users are stuck with safari, and there is literally no way around it.

Nope. Smartphones get replaced more regularly, and with less compatibility headaches than Desktops.

XP reigned for over a decade. No iOS version will be widely used for nearly that long.

You could also argue that Safari on desktop is more likely to be updated as well since it is generally accepted that Mac OS X has a higher adoption rate of new versions since:

1. enterprise use of Mac OS X is pretty small, and its generally enterprises that are slow to upgrade OS/browser, etc (albeit for generally valid reasons) 2. OS X upgrades have been free for some time now.

no