OP
Due to the volume of messages sent, it only takes a very small response to be worthwhile. Potentially if just a couple of people were to take up the offers/services/products being touted, it's money well spent for the spammers.
There is very little human involvement once they have a foothold (normally an authorised account or server compromise - as happened to me a while back).
Sometimes the aim is not to generate revenue directly, but to get links on pages that are indexed by Google. This site appears alot when you search for electrical related stuff and it's usually quite high up in the list... links from here to other sites have a positive impact on the target sites page rank so they'll appear higher in the search results. The problem with this is, Google changes the page rank algorithm from time to time so it may not be as beneficial today as it was say 12 months ago.
But I have been contacted by a company in the US who claimed someone had posted unauthorised links on the site I managed... and they had, there were tons of them. Now spammers don't post links unless it's in their interest or they are being paid to do it, so draw your own conclusions, but based on my investigations into said company, they were a real shady operation dealing with medical related qualifications and they were responding to a change in the page rank algorithm that if I recall correctly meant links from sites on unrelated subjects resulted in a drop in your page rank... Google responding to abuse by spammers
@darkwood - I'm not suggesting custom modifications as I know what a pain they can be to upgrading server software. I was just putting the idea out there with respect to what features are available in XenForo. For instance, I know XenForo has a warning system built in (which, from my limited knowledge) is available to staff and moderators. From what I've read about the product it also has the ability to ban/discourage people. Given user groups can typically have these rights assigned to them (a moderator will typically just be someone who is a member of a particular group), it may be possible to grant the ability to warn people to more groups (as I said, members of the Arms and TAs - since we are, well the majority of us at least, all adults and hopefully beyond the childish behaviour of trying to get someone banned because we don't like them or what they are saying).
I wouldn't propose automatic removal of a user, just a ban that prevents them from accessing facilities that allow them to post. Thus, staff can review/deal with them appropriately at their leisure, but in the meantime, the site isn't subjected to a torrent of spam.
It was just a thought I had to try and improve things
