I was about to say the exact same thing. A lot of rules of writing happen to be current trends in literature, not actual hard and fast rules.
Adverbs are a useful language construct; if you teach people not to use them, they'll end up with a stilted grasp of writing rather than a balanced one.
For example, from the article:
> In our next class, I pointed out that using an adverb as a means of revealing a character's thoughts or actions was almost always a tip-off that the writer is telling instead of showing. For example, if I write:
> Nancy yelled angrily whenever someone questioned her.
>...I'm getting my point across by telling the reader how the character reacts. Sure, this might be just fine at times, but it's often better to write something like this:
> Nancy's boss approached holding the report she'd turned in the day before. She felt her heart start to race – what was the problem now? She'd met her deadline. The clients would be happy.
> "Hey, Nancy," Jim said. "I just wanted to ask you if you're sure this is ready to go out with the courier. Did you double-check it? Triple-check it?
> Nancy felt her face heat up, and the words were spilling out before she could stop herself. "What do you think, Jim?" she said, as she took a step towards him. "Did I remember the most basic component of submitting a report? Did I?"
But this is completely ignoring the negative effect: You've replaced one line with a dozen or more. You don't necessarily need this, some things in your story can be glossed over. If you don't want your book's word count to spiral out of control, maybe you need to cut some of this wasted text that's better represented by a simple adverb....