kaled - 2:39 pm on May 29, 2010 (gmt 0)
I agree almost entirely with encyclo. However...
I do believe white-lists (and black-lists) have a part to play. In the example above, the fact that the domain was not on a white-list should not have blocked the link. A link should only be blocked automatically if the domain is on a black-list. Otherwise, it should fall to moderator discretion. However, a white-list would a) act as a guide for moderators and b) reduce their workload since such links could be passed automatically.
As an extra technical point, it would be nice if links were validated when posted. We've all seen bad links and these could be easily detected before the post is accepted.