Despite what investors think, I couldn’t be happier with Twitter’s first earnings report yesterday. That’s because the Social Media Insider delights in being right.

Though there are many numbers on the release, the two categories SMI is right about -- and everyone is paying attention to -- are these:

1.     Revenue: Of course, most of Twitter’s revenue comes from advertising, and that’s looking up. Q4 revenue was  $243 million, up 116% year-over-year; for the full year, revenue was $665 million, up 110% year-over-year; the company actually beat estimates. Its ability to insert advertisers into the conversation is clearly resonating with them.

2.     Users: A gain of nine million users in the last quarter, with only one million coming from the U.S. User growth is slowing Timeline views -- Twitter’s key ad engagement metric -- declined sequentially, to 148 billion from 159 billion.

Since the earnings came out, investors have chosen to focus on the not-so-bright side -- the user metrics -- and that has caused Twitter’s stock to drop; it is down more than 14% today at this writing.

What those two categories of numbers show is what I’ve been saying all along: that Twitter is uniquely strong as an advertising property, but hasn’t been spending enough time expanding and enticing its user base. Investors are rightly concerned.

But unlike some of the opinions I’ve read, which posit that Twitter is too complicated to use, I’d venture the problem is something different: People don’t know what to do once they get on Twitter. Follow celebrities? Subscribe to newsfeeds from CNN and The New York Times? Click on trending topic hashtags? Find friends?

It’s not that using Twitter is hard. Any idiot can type 140 characters into a box. Figuring out why you are there, however, is -- because there’s no one simple answer to the question, an irony for a platform built on short messaging. On Facebook, you’re there to connect with your friends. On Twitter … ?

I first joined Twitter in about 2006 or 2007, because it’s my job to try out new platforms; that’s a clean, easy reason to be there. The first account I ever followed was @deltaairlines because back then, a corporation with a Twitter account was news. I don’t really think I used it, though, for at least six months afterward, for the same reason the accounts of many so-called Twitter users lie dormant today: I didn’t know what to do after that. One gets the feeling that a lot of people “walk in” to Twitter by setting up an account, but look around the joint, have a hard time figuring out where the party is, and walk back out.

Eventually, of course, it began to make more sense to me, as more of the media and tech-obsessed people I hang out with professionally came aboard. And while I certainly spend more time on Facebook these days than Twitter, it excels at certain things that Facebook doesn’t. It’s absolutely indispensable during the conferences I run, when the tweetstream helps to bond attendees together; during live events like the Super Bowl; as a distribution and feedback channel for this column; and during other times when I’m trying to stay up on news that matters to me, like whether or not Gmail is down.

(I’ll add that the egomaniac in all of us loves to see our status updates on Facebook “Liked” and commented on, but on Twitter, the recognition is sweeter, because it’s more public, and sometimes comes from people whose circles you can only hope to run in. Silly remembrance: the time @craignewmark retweeted something I said about “The Daily Show.”)

But none of the things I enjoy about Twitter loops in people from my personal life. That is Twitter’s slowing user growth being boiled down to one Twitter user’s experience -- anecdotal, but telling.

At the outset of this column, I said I was happy about Twitter’s earnings because I was right. Snarky, eh? Actually, I’m glad for another reason: it creates impetus for this phenomenal social platform to finally get serious about broadening its appeal.