(Just popping in for a flying visit to Slashdot)
deviantART has been getting a LOT of spam and phishing attacks, in part because there are so many users on their likely to fall for such things. Hence disallowing posting from newly-created accounts. They also have an interstitial screen for all outbound links, which is annoying to say the least, and the latest has been to add a link symbol next to outbound links in messages.
Unfortunately, there are still ways around the spam filters. Most spam accounts I spot have laid low for a while before posting, so they don't get closed until people have reported the messages, by which time they've probably gotten what they came for. :( And the actual reporting system still needs some works.
(I'll have been a dA member for 10 years in a few weeks time. The site does look a lot better than it did back them, unlike a certain tech news site I can think of...)