Twitter posted fourth-quarter 2014 revenue of $479 million — up 97% year over year — and beat analysts’ earnings estimates for the period.

The No. 2 social service (behind Facebook) had 288 million average monthly active users in Q4, up 20% from the year-earlier period. But Twitter reported a net increase of only 4 million MAUs from the previous quarter, disappointing the Street, with the company blaming in part an issue with Apple’s iOS 8 update.

Twitter reported a net loss of $125.3 million for the quarter, which included $177 million of stock-based compensation expense. Its adjusted non-GAAP net income excluding that was $79.3 million, or 12¢ per share. Wall Street analysts had projected adjusted EPS of 6¢ and $453 million in revenue, according to a Thomson Reuters survey.

“We closed out the year with our business advancing at a great pace,” Twitter CEO Dick Costolo said in announcing the results. “In addition, the trend thus far in Q1 leads us to believe that the absolute number of net users added in Q1 will be similar to what we saw during the first three quarters of 2014.”

The strong 4Q revenue growth and improved full-year 2015 guidance “reduce our concern on monetization expectations,” Morgan Stanley analyst Benjamin Swinburne wrote in a research note. While user growth lagged in the most recent quarter, he added, “1Q user growth appears to be accelerating to the low teens versus our prior estimate of 12 mm, which is encouraging.”

Last month, the company noted in its earnings release, Twitter launched a new video feature that lets users capture, edit and share videos up to 30 seconds from within the Twitter mobile app. In addition, the company debuted a recap feature with a “while you were away” heading that displays top tweets, as well as a group-based direct messaging feature for private conversations involving up to 20 people.

Costolo, on Twitter’s earnings call Thursday, said video growth has been strong. The company now delivers 1.5 billion Vine looping videos per day, and he said the Twitter Amplify program for video-enabled advertising tweets from media partners has been expanding.

Twitter is now syndicating advertising on third-party websites, and has initial deals with Flipboard and Yahoo Japan, Costolo said. In addition, Twitter has an agreement with Google to index tweets immediately as they’re posted in the search engine, which Costolo said is aimed at driving traffic back to Twitter.

The company said that for the first quarter of 2015 it expects revenue to be in the range of $440 million to $450 million, with adjusted net income of between $89 million to $94 million (excluding stock-based compensation expense of $160 million to $170 million).

In Q4, Twitter said, it lost a net 4 million users who upgraded to Apple’s iOS 8; about 1 million of those didn’t access the Twitter app after the update, while 3 million users that Twitter had counted as active users stopped getting updates from the service in the Safari browser. Costolo said “seasonality” also hampered user growth in Q4 2014.