I'm in the aftermath of preparing some talk slides and I'm going nuts over it!
Please: when you share images (like group photos, screenshots, cake) on the wiki,
don't just put them under CC-Attribution-ShareAlike License (or state that they are, if you are not the creator), but also NAME THAT ATTRIBUTION!
It's not enough to write CC-BY-SA under each picture. Put a name (or an acronym, nickname, website name, company name etc.) beside it. If you are the creator, you are free to choose how the attribution has to be done, but you have to actually do it!
If you just uploaded an image from someone else, then try to find out how the original creator wanted to be attributed.
For a group of people who care a lot about licensing map data, we care surprisingly less about the stuff we share on the wiki. Wikipedia does that a lot better, but they actually learned through very expensive mistakes.
(Yes, I know I could just attribute everything to openstreetmap.org if no one other is named. I would be out of harms way, but that is not how the license is meant and it's hardly fair to the original creator.)