With resources embedded in the highly "compressed" base64 encoding. Quite a few email services will probably block those html files just because they end up stupidly large unless your content is text only and doesn't include half a dozen java script frameworks to manage basic animations.
Those same email services blocked SWF files too because they were dangerous. This is no different.
As for size, browsers really should allow gzip encoding for html files from your desktop. Would pack all the inlined crap down to a reasonable size and then you could transfer things around better.
