I think it must have been something more than just that link. Maybe the timing just aligned with some other algo adjustment at the same time?
We are successful using both article marketing and directory submissions as a part of our overall marketing plan. I think its a pretty broad brushstroke to use, painting it all black like that.
Directories - We stay niche focused, relevant, and manual. We also do reciprocal links when we find one that will be useful to our visitors.
Articles - We go one to one and ask webmasters to use our expert content regularly. Rarely are we turned away.
Sure, there is plenty of bad out there when you start talking about using automated tools to do these things, but high quality directories related to your market, and high quality articles written to the readers of the site you are writing for, is not bad in our opinion.