Flash, the media plugin from Adobe, is pseudo-ubiquitous on the web. It’s used on nearly all large websites, but often in form of useless additions such as ads. There are a few uses of Flash for rich applications (e.g. Mint), but often it’s just a distraction. Furthermore, and particularly on the Mac, the plugin can slow down your machine and consume resources.
Enter ClickToFlash, a Safari plugin that gives you control over which Flash objects to load and when to load them. You can “whitelist” certain sites, so Flash you actually want to use gets loaded automatically. For other sites, you can, well, click to Flash, allowing you to selectively load objects.
Check it out, it’s free. So far, it’s worked nicely for me.