The spam blacklist is helpful but suffers a bit from lack of whitelisting, since
it's ofetn useful to block a whole domain. That in turn can affect innocent
subdomains which have already been used in articles.
A flag to turn on acceptance of even matching URLs if they are present in the
version of the article being replaced would be helpful, to reduce inconvenience
for existing articles. That is, effectively an automatic whitelist for a URL
already in the article. Most blacklist complaints would be elimiinated by this