I'm not a big fan of prohibitive IT departments, but this article is probably as biased as you'd expect an article from a major SaaS provider to be.

I witnessed the shift from a very restrictive environment (central SVN accessible only through VPN, all authenticated through Active Directory, limited access to servers) towards "the cloud" (Google Docs, Github, AWS, etc) at my last employer. While the latter has it's advantages, but it's not all rainbows and unicorns.

One major issue is user management. I quit yesterday (self employed now, yeah), who ensures that my accounts gets deactivated on all these services? With a centralized approach, it's just one click.