Having HTML functionality on these threads is a bit of a double-edged sword - it's great for creating thread headers with graphs/charts/pictures etc., but as we saw last night it's open to abuse from those with malicious intent.
I wouldn't complain to ADVFN though as the last time someone did that they removed HTML functionality altogether and numerous thread owners (myself included) inadvertantly wiped out a number of thread headers which had been painstakingly built and developed over time. Not good!