While there are some UK-specific terms thrown in here and there, a simple preview of the activity yourself will determine if it's significant enough to be a concern. (I'm willing to bet it won't be.)
I can see these activities used in a whole-class setting for formative assessment, to introduce topics or reinforce skills, especially where Interactive White Boards (IWBs) are available. Bring students up to the board and let them explain how they are solving the problem! The site could also be used effectively in centers, especially given the ease of navigation. Finally, since each activity has its own unique URL, it's easy to add Favorites or Bookmarks to local browsers, making immediate access a snap.
Are you a little hesitant to create videos? Masher makes it's easy. You can "mix, mash, and share" video clips, audio files, and photos into polished movies. Students own content as well as media from the BBC Motion Gallery and Rip Curl free for the mashing, and can then be shared on social media sites or via email.