I ran into a very strange problem today. I saw a fantastic question that I wanted to know the answer to, but the question was only aimed at a particular platform, which didn't happen to be the one I was interested in.
Should I repost the exact same question for the platform I am interested in, or update the question (when I have enough reputation) to account for multiple platforms?
I'm thinking about what the end result of these situations is. The answer is either going to be indubitably identical between the consoles, or drastically different. The latter case is good reason to not hijack the question by editing it into a new one - this will invalidate the original answers through scope expansion. I also considered suggesting the posting of a bounty on the question, accompanied by clarifying your need for a different platform in comments. However, that will end up with you attracting answers onto the question which don't seem to quite address the console that the question is about and is tagged with.
Because the answer will be radically different, it should be fine to post a new question. It can help your case to explicitly identify the first question in the body of your question, noting that it only works for a different console. This not only keeps the answers relevant to the original question, but also couples your question with it through the Linked section. Consequently, you will either get answers that tell you what different steps you need to take for your platform, or politely informed that the solution is identical to the methods used in the other platform.
These scenarios will not generally come up that often for each multi-platform game, so I don't consider that we would be in any danger of being flooded by these reduxes of questions. For the record, Stack Overflow does occasionally get questions like "What is the Java equivalent of what this C# question asked for?", and they stay open and get good answers.
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.
