Actually, my experience is that .swf files and .flv files can be uploaded to Cloud but can not be played within Cloud or when shared from Cloud. Curently video preview in Cloud is HTML5 so .mov and .mp4 files can be played from within Cloud.
At present, this is correct. You can upload and download .swf and .flv files like all other files. Creative Cloud has additional functionality around certain file types that enables you to view individual layers (.psd) or artboards (.ai) or pages (.pdf, .indd) directly in the browser. We will be adding additional capabilities like this for other formats in the future.