The video stream source can be seen simultaneously at home(thru a regular tv) and thru slingbox. The slingbox stream can only be sent to one device at a time(which could be a laptop, pc, iphone/ipad, etc). Just remember that there is only stream and no individual control. Its like 2 tvs hooked up to one cable box. You would need to create a second stream source(splitter to second cable box, etc) to watch different things.
As far as i know, ....
You can connect the coaxial cable wire to the slingbox, in addition to a cable box connection, to make two different input sources to choose from. If the home tv is watching the output of the cable box, you can select the coaxial input and watch any channel on it independently, with its own unique remote, without interrupting the home tv. (You may even be able to have additional sources connected as well, but haven't confirmed that). Note that with the coaxial source, you will only be able to watch the analog channels that a cable-ready tv could get - up to chanell 99 and not HD. You'll also need to buy additional software to connect with an ipad. (Consult the slingbox sources for that)