We're always on the lookout for spam. Actually we stop literally hundreds of posts on a daily basis through various automated preventive measure. Of those posts that do get through are scanned and some flagged for review. There is clearly room for improvement despite of the current measures. Unfortunately preventing links for new posters is not something we can implement in a straight forward manner at this time. I will have some news in the next few weeks that will hopefully improve things on the spam front.