On Super User, a post that uses the `blockquote` markup displays a graphic "bar" on the left edge of text. It is really useful when trying to display a quote within a quote. Can it be implemented on the other services (SO, SF, Meta)?

Super User Blockquote:

![](https://i.stack.imgur.com/YeZH4.png)

Stack Overflow Blockquote:

![](https://i.stack.imgur.com/0puME.png)