Christmas incubater spin
To me it seem what they meant is u get a incubater everyday u spin a pokestop that has a pic of the place , like church, park etc .. the pokestop that have a drink or company logo (sponser one) they wont give any .. seem like they giving you a incubater everytime u spin ur first unsponser pokestop of the day
Answers
It will be once per day on any pokéstop, all of them have photo disc you have to spin ;)
The only doubt is if you still will get the incubator after missing the first stop of the day, because they said every day after your first spin...I am holding my spin with my 7 days streak just in case, I don't want to lose that incubator, I have already made my gym run and I have like 400 balls combined so no hurry to get to stops, but it seems we gonna get it in like 7 hours or so, by that time it will be evening-night here...
I wish everyone can get their 10 incubators but we are talking about Niantic so expect the worst...They have always worked like USA/San Francisco is the only one that matters for them, they have made their point clear, rest of the world is not such important, new tracker benefits high dense cities with lots of stops and was released there only for months while made us wait and wait and wait, and the same thing with the events, they seem to have priority with events like halloween and thanksgiving over others that are worldwide, so my guess is probably a lot of people will get one day less of this event.
If I were you I would wait as much as you can but never go to sleep missing that 7th stop streak, 20+ items and xp are too good to be waiting for this company, if this night the event has not started for me I will make the 7th spin for sure ;)
That what they meant by photo disc pokestops .. like sprint n starbuck, ect spawn a pokemon around there pokestop to get people to go .. im guesting they are putting incubater to make ppl go to the unsponser pokestop since everyone say they get stuff they dont need like revive n everything else so they using a incubater lol