You can grab URLs or add notes straight from the browser via a Chrome extension.

Any item can have a free-text comment, which can be shown or hidden as desired.

Checkvist offers many free features if you are using this individually.

Checkvist hits a sweet spot between minimal and complexity. It gives you a host of options and extras to use on your lists, but you can completely ignore them if you don't need them and keep it very simple. This makes Checkvist a one-stop shop, regardless of what type of 'list' you need.

To-do lists often need to be grouped and regrouped for clarity. The outline-based nature of Checkvist makes it easy to move things across categories, to increase and decrease priority, etc.