@Jill: Sorry for the confusion. This is caused by recent security features built into Firefox and Chrome. It occurs because the browser sees the iFrame (which uses http) embedded in the main site page (which uses https). You can find more info on this at:
http://goo.gl/rL2GNSThe solution on Chrome and Firefox is to click on the little Shield icon in the top right (Chrome) or top left (Firefox). That loads the content, but marks the page as unsecure -- i.e., it places a special symbol on the https icon or text. Check out this short Screenr movie I just created:
http://www.screenr.com/r0bHFinally, SME's post comments in the Wiki or on a Google doc embedded in a page on the wiki. Works pretty well as long as you train your SME's and remind them to use the wiki.