These bbs systems are notoriously un-secure. I've been able to embed way more stuff into posts than any sane system should allow. It allows freaking JavaScript in the post, what kind of shit is that? You shouldn't be able to do the following on a bbs:
Wheel Size Calculator:
<form action="" name="wheel_info">
Enter Tire Size: <input type="text" name="wide" size="4" maxlength="3"> / <input type="text" name="ratio" size="3" maxlength="2"> / <input type="text" name="wheel" size="3" maxlength="2"> <br>
<input type="button" value="Calculate" onclick="javascript:document.wheel_info.output_zone.value = (new Number(wheel_info.wide.value) * new Number(wheel_info.ratio.value) * 2.0 / 25.4) / 100.0 + new Number (wheel_info.wheel.value);"> <input type="reset" value="Clear"><br>
Wheel diameter: <input type="text" name="output_zone" size="5" maxlength="5" value=""> inches<br>
</form>
But, as long as nothing truly important goes on on the bbs, it's really no big deal when it gets hacked.