Time-consuming and very resource intensive, I should say. The mods are already handling tons of reports and requests every day with the same nature of approach. Also, some mods are doing work voluntarily and not really paid that much (CMMIIW) by this forum. Hiring more mods doesn't necessarily solve the issue of spam, and this might seen as somewhat controlling the freedom of newbies and lower-rank members to post whatever they like (lol). If you happen to see such posts that does not go well with the topic or is somewhat inappropriate to the board in which it was posted, the report to moderator button works wonders.