Spammers are always trying new ways to dodge around spam filters; this is part of the reason why no spam filter is 100% effective. Net Access responds to new techniques by altering its spam filtration rules, but we can't make the filters too strong in scope or they will block too much legitimate email. The spammers, on the other hand, are not restrained at all by any rules and can try any trick they want to get around our filters. If you're getting too much spam that you think should be filterable, try setting your spam threshhold to a smaller number.