If you saw the headlines yesterday, you might be excused for thinking Twitter was in decline:  “Twitter's growth slows dramatically,” “Twitter popularity declines, growth slows down,” and “Is Twitter 'Traffic' Tanking?”

Twitter was the story of 2009, growing from less than 5 million monthly users to almost 30 million in the course of six months.  People joined, brands rushed in, and words like “Tweet” entered our common vocabulary. 

It was a heady year for Twitter, but has it had its day in the sun?  What do the headlines mean?

First of all, Twitter isn’t going anywhere any time soon.  It’s become ingrained into consumers’ and companies’ communication channels.   And it’s just getting started—under development are more tools to help enterprise customers manage and learn from the billions of tweets produced globally.

Secondly, who said Twitter is for everyone?  It serves a great purpose for many people, but it lacks Facebook’s wide range of applications (and thus wide appeal).  It also lacks a great deal of the noise that many find makes Facebook a less than ideal business networking, news, and sharing environment. 

Lastly (and most importantly) is what the headlines are not conveying.  Yes, overall growth is slowing—how could it not after posting 1,000%-plus growth in such a short time?–but the key for marketers is not the number of Twitterers but the habits, Technographics and psychographics of Twitterers.  As Sean Corcoran and Josh Bernoff demonstrated in their December 2009 report, “Who Flocks To Twitter?,” Twitters are the connected of the connected, overindexing at all Social Media habits.  For example, Twitterers are three times more likely to be Creators (people who create and share content via blog posts and YouTube) as the general US population. 

Twitter’s growth may slow (or perhaps it will see an @oprah-like bounce now that @billgates has joined and is generating PR), but its value to those who Twitter and to marketers is not in question into the very foreseeable future.