The story talks about the "revolving doors" of leadership at Twitter and other issues. Specifically, the sub-title of the article pretty much sums its basis: "Boardroom power plays, disgruntled founders, and CEO switcheroos are clipping the wings of this tech high flier."
"U.S. traffic at Twitter.com" has "leveled Off" in the past year, it says, though this is hardly indicative of user interest in Twitter, given that it's wordwide (and instrumental in revolutions), continues to be nearly everywhere in the media (not just stories about Twitter, but the media actually using it), and a great deal of users access the service in ways besides going to Twitter.com.
Co-founder Biz Stone put up a blog post in response to Fortune. He wrote, "What took so long for somebody to write the article that says we are falling apart? The normal press cycle is to put a company on a pedestal and then knock it down. It's much more interesting that way. Twitter has had so many ups and downs you'd think we would have had more negative press. To me, it's like watching the movie Rocky—he's up, he's down, he's out, he wins!"
Twitter continues to have "Fail Whale" issues on a regular basis, despite efforts to reduce them. But it doesn't seem to deter users much. That's a good sign. How many sites/services that you so often have trouble connecting to would you continue to use?
'Fortune magazine finally stepped up to knock us down with a cover article, 'Trouble@Twitter.' Here are some examples of how this works," continued Stone. "After mostly positive coverage of Facebook, Fortune finally published an article in April of 2009 titled, 'Is Facebook Losing Its Glow?' However, later that year they published, 'What Backlash? Facebook Is Growing Like Mad.' Google received similar treatment. In July 2010 Fortune published, "Google, The Search Party Is Over.' Later that year, they published, 'Google Continues To Gain Search Marketshare.'"
The bottom line is that big brands (this includes celebrities, politicians, etc.) will always get both good and bad press. That's just how it works. The more attention you get, the more scrutiny you get. The bad is often exaggerated, but then again, so is the good.
As far as Twitter U.S. traffic leveling off, the recently-returned Jack Dorsey has made one of his biggest priorities getting users to realize why Twitter can be useful to them. Since his return (just last month), Twitter has already tested a new homepage and updated its search feature with greater focus on user discoverability. They've also made Twitter Search three times faster.