A List of Things That Plugins Don’t Work With

Browser context menus

No “Save Page As…”, no “Send Link”, no “View Background Image”, no “Open With Editor…”, no “View Page Source”, no “Inspect Element”…

Printing

Cannot print using your browser’s print function and expect a multi-page document.

Bookmarks

Cannot bookmark parts of plugin-based content.

Password manager, sync

Just remember it, okay?

Cookie settings

“Screw you, and your privacy”.

Caret-browsing text selection

Cannot fully navigate using the same conventions as the browser.

⌘ + Click

Cannot choose to open a part of plugin-based content in a new tab
(like viewing gallery images in tabs).

Browser extensions

Browser extensions cannot operate upon the text or images within the plugin.

User stylesheets / User scripts

No accessibility override, like your choice of fonts and colours. No customisation. No patches for broken browser support. No “No Style” choice.

Drag and Drop

Cannot drag images out of the plugin to save to disk.

Zoom text-only

Cannot scale the text with the rest of the page.

Error console

No Firebug or Web Inspector. No source code. No breakpoint debugging.

There is no job that plugins are the right tool for.
Saying that plugins ‘have their place’ is ignorant and complacent.