Hot topics has a slow update delay.

xBlueXFoxx

Basically what the title says, it updates slowly, like once every 5 minutes.

sona458

I agree.

xBlueXFoxx

On the other hand, this may be delayed for bandwidth reasons. I would say for unregistered guest users have a slow update rate, for registered users, increase it. I do not see it effecting bandwidth too much however.