A lot of the time it probably makes a lot of difference what the platforms are, a lot of the time it may make no difference. I don't think this is going to be something there can be a solid rule for.
Same generation consoles will be very similar for many answers, but will differ in small ways. Portable versions of games are often an entirely different game engine, written by a different developer, so will differ in a lot of ways (eg Force Unleashed on PC/Xbox 360 written by one development studio, on the PSP/Wii written by an entirely different dev with none of the fancy in-engine effects).
Finally PC versions will give a lot more options for many answers.
For instance a question like how do I beat level [x] of game [y] may well be be identical between XBox 360 and PS3, and the same other than controller differences on PC.
Whereas other questions may be answerable on PC/Mac because you have a lot more access (eg my question here) but be impossible to do on a console.
Others like the example in the top question will vary between platforms due to entirely different interfaces to the base system.