Iframes can't be used in forum posts or signatures. Flash is not possible to use on the forum section of the stie.
Iframes are extremely insecure, so not iframes. Flash is also pretty insecure, can lag people out and is... well.. pretty bad. So it's very unlikely.
neither would ever be allowed. it would allow people to infect everyone with viruses... cant have that.
Multiple anti-viruses would flag EMC as 'unsafe', people will not want to visit a site where they could potentially get a virus... this is what happens if we were to use iFrame/Flash. It's extremely insecure and unsafe. Stick to .gifs
Change your .swf to a .gif. If the swf file is a game or something, it won't work. If your swf file is playing a video or something, just change it to a gif.
Ok well if you look at this you will know why i wanted flash: http://share.snacktools.com/F9C7A87D75E/btplw985