This is a place to have conversations, much like many other such places on h2g2 such as Ask, The Forum, Misc Chat etc.
Here, there is but one rule, one guiding theme. Conversations here should begin with "What if..." and invite speculation.
The topic could be serious or frivolous, scientific or supernatural, politicial or philosophical, religious or grown-up, light-hearted or melancholic, long-winded or concise.
Just pose the question and see who can take it to its logical (or illogical) conclusion.
There are two ways to contribute:
1. pose a question
The only advice offered here is try to make it something open-ended, something that would result in an actual difference in the world. "What if Liverpool played in blue?" doesn't really suggest an earth-shattering parallel reality. "What if everyone knew the exact date and time of their death?" gives endless scope for speculation on the effect on society and the human condition.
2. respond to a question
Ideally, resist the urge to respond with "What a stupid, pointless question." This is an internet site. Everything on it is, practically by definition, stupid and pointless, beyond some ephemeral entertainment value. These conversations should have no pretensions to be any more significant than shooting the breeze down the pub. That said, you can learn some interesting things down the pub.
If you do want to respond, go for it. Take the question and run with it, use your imagination, go the very end of the rope, cut it and keep going.
Note: the point of these questions is NOT to ask if the thing being proposed is a good idea. That may be obvious one way or another, or undecidable even in principle. The only point here is to speculate what would actually HAPPEN if the conditions described came about. Asking "What if X?" should not be taken as in any way suggesting that X is a good idea, or condoning the idea that X is acceptable. This is about speculation on consequences, NOT advocacy or opposition*.
Some examples are provided by the author to get you going. If you like the idea, you might like to subscribe to the entry to see the questions other people propose.