On the other hand, if the spam is mid-way down a legitimate thread then the fewer responses there are to the spam, the more sense the thread makes once the spam has been deleted / the les work there is for moderators. I moderate a health-related forum, and on one occasion deleted a spam, didn't notice that the message after it was a scathing attack on the spammer, and nearly ended up causing a blazing row between her and the previous legit poster who thought HE was being attacked! What I should have done was do the extra work and delete the messages after the spam that referred to it. So, answering spam that appears in legitimate threads make extra work for the moderators.