Twitter was founded in March 2006—almost 12 years ago. In all that time, it never made a penny in profit until just last quarter. Twitter's Q4 2017 results show the company made $91 million. That's up from a $21.1 million loss in the previous quarter.

Turning a profit is obviously a big deal for Twitter, but it's not only the profit that matters. The company has also seen a year-over-year revenue increase for the past four quarters. That points to continued growth in the business. Although, it didn't add any users in Q4. That's not necessarily unusual—Twitter has even lost users in some previous quarters. Still, Twitter's daily active users increased by 12%. So, it didn't get more users, but the ones it had were more active to look at ads.

The stock market is liking Twitter's report. Its price shot up about 20% at the open, but it's backed off a little since then. As of this posting, Twitter is up 15.6% to $31.14 per share. If Twitter manages another profit this quarter, it might have finally turned a corner.