Twitter keeps disappointing the street.

The social media company reported its first-quarter earnings on Tuesday, and revenue was up, but not up to expectations. Analysts had predicted just under $608 million in revenue for Twitter (TWTR) in the first quarter, which would have been a 39% rise from the year before. Instead, the company posted $595 million. It also lowered revenue guidance for next quarter, to a range of $590 million to $610 million. Twitter beat nicely on earnings per share (EPS), reporting 15 cents where analysts had estimated 10 cents, vs. 7 cents in the first quarter of last year.

And Twitter beat expectations for monthly active users, adding 5 million for a total of 310 million, vs. expectations of 308 million. (The user count no longer includes SMS Fast Followers, users who add Twitter via text-message outside of the U.S.; It is a group Twitter was criticized for including in past user totals as a way to goose their numbers.)

User growth, of course, is always the big story for Twitter. Last quarter was an unmitigated disaster: Users declined for the first time. It has helped fuel a negative narrative, in the tech media and on Wall Street, that Twitter can no longer attract new users. (It is why the company launched Moments, its news-summary feature to try and demonstrate Twitter's value to skeptics.) The user numbers for this quarter, at last, were encouraging.

It didn't matter. Twitter stock is down more than 9% in after-hours trading, and still falling at the time of writing. The stock has been getting hammered for the past year, down 24% since January, though it is up more than 13% in the past month.

The key to why the earnings aren't good enough and the stock is falling is this line in the company's shareholder letter: "Revenue came in at the low end of our guidance range because brand marketers did not increase spend as quickly as expected in the first quarter." Translation: Advertisers still aren't as convinced of Twitter's value as Twitter needs them to be.

In the letter, Twitter reaffirms its position as the go-to place for live content. (The letter even employs the word LIVE repeatedly, in case you forget.) "We're focused on what Twitter does best: live. Twitter is live: live commentary, live connections, live conversations. Whether it’s breaking news, entertainment, sports, or everyday topics, hearing about and watching a live event unfold is the fastest way to understand the power of Twitter."

The problem is that Twitter no longer owns that niche.

Snapchat has seen huge success with its live stories, which include user-generated footage as well as Snapchat-produced footage and are viewed by an average 10 to 20 million users per day. Two times as many 18-to-24-year-old watched the first GOP debate of the presidential election on Snapchat as watched it on television.