Wikispaces is closing down after more than ten years of service. You can read the sad news here on their blog post. I never used Wikispaces in my teaching. I tried to set some events and units up using the service but just couldn’t get past some of the user interface and difficulty with some of its formatting.
I do remember a teacher who planned out his entire two year curriculum in a Wikispace. He taught an IB economics course which spans two years. All the readings, videos, worksheets, exercises, discussion topics, articles and more was meticulously planned out for each day of the two years! It was/is impressive. He is a great teacher and this was his textbook, his three ringed binder, his Common Core curriculum.
I know of other teachers who used Wikispaces as a way for students to collaborate before Google Drive, Office 365 and other collaborative spaces existed. Wikispaces was certainly a big predecessor for sites like Weebly, Wix and more.
I know some people will miss the site and others will be completely oblivious to its absence. Either way, it was an important part of the development of the Web 2.0 movement.