Good catch Rose! updated readme.txt for Step 2.
Will look @ spoilers. Gotta make sure that it doesn't spoil the spoiler too!!

Holy moley, the POST_BODY impact for a spoiler is huge. it's over the 450 character limit, so html->truncate kills it.
That's the nature of the spoiler tag as it is stored in the database.
Even upping the limit to something larger in the truncate(450) call, doesn't fix it either soooo..
For now, it will have to stay as is.. i'll see what i can do with the truncation as to some special cases. i've noticed embedded vids don't get previewed either, but these are more rare than common.