So here is a quick tip. If you are recording presentations in a tool like Camtasia and you have the ability to record both the microphone and the system audio (in order to record audio as well as your voice when you are recording an embedded video in your lecture) your file size will increase exponentially.
A recorded Prezi of less than two minutes that used embedded video with sound resulted in a 22 MB file. A five minute Slides presentation that only used voice from a mic and some animations resulted in a file that was only 10 MB.
File size can be a big deal if you are sharing it with an online community. The recorded Prezi is too large to post on this Engage site.