Well, yes they do, only it's different with and without CTRL. For example in a text editor (or a normal webpage without any fancy JS):
- Shift+End goes to the end of the line
- CTRL+Shift+End goes to the end of the document
and the same is true for Home (substitute "end" with "beginning").
I have seen people, even "technical" people, select a text with the mouse from the middle of a large Word document to the end, because they didn't know this.
They also had to do it often (several times a day) and it had become a significant part of their workload...
>CTRL+Shift+Home selects all from where you are to the top
Those two don't need CTRL, just so you know.
>One of the (many) problems of web UIs is they often ignore the keyboard completely.
They are also starting to ignore the mouse.