I have a suggestion for this thread:

Once a puzzle is solved, it would be very cool if the author of that puzzle would edit the original message, and post some sort of answer/information/links within a "spoiler" box... like this
Click to reveal.. (The Answer)
The explanation can be hidden here.

Multiple lines can be included...

Even links.

To make something like the above, all you need to do is enclose the hidden text within a [spoiler:The Answer] ... [/spoiler] pair of tags.