The Paper add-on for Firefox sends an article to Instapaper by shift-clicking a link, doesn’t make any noise and is pretty customizable. Great for adding links from one page in a bulk, you just click on each one and there you go.
Here is more about the add-on from the developer:
There was always the same damn problem with each of Instapaper browser extensions: they were unpractical to add links in a bulk. You should open the page and only then you could send it to your Instapaper.
Then I have found one for Safari, great extension indeed, but I am Firefox kind of guy, so here it goes.
It’s pretty customizable, but by default you add links just by Shift-clicking on them. A button is also there. You can also make a hotkey to save the current page without pressing the button, but it is turned off by default.
Want to pick up Paper? You can get it at the Firefox Add-ons website.