E.g., if you have the QuickTime plugin installed, then your browser can play embedded QuickTime movies.
Web content plugins are not new - they date back to Netscape in the mid-1990s. Safari extensions are the things Apple lists here, and which you manage via the Extensions tab in Safari’s preferences window. They’re written using JavaScript (and HTML and CSS for presentation, if they present a user interface). These Safari extensions are much like Firefox extensions. Earlier this year, Safari 5 introduced a new, officially supported extension API. That sounds pedantic, perhaps, but bear with me.
The original ClickToFlash is a plugin, not an extension. Previously, I used and recommended the excellent ClickToFlash plugin for Safari. I’m really happy with this setup, so I thought I’d document it here. Last week I mentioned that, following Steven Frank’s lead, I’d completely disabled Flash Player on my Mac. But I have a cheat, for web pages with Flash content with no non-Flash workaround. Going Flash-Free on Mac OS X, and How to Cheat When You Need It Thursday, 4 November 2010