Twitter had 288m MAUs in Q4 2014

"Twitter, Inc. (NYSE: TWTR) today announced financial results for the quarter and fiscal year ended December 31, 2014.
• Q4 revenue of $479 million, up 97% year-over-year
• Q4 net loss of $125 million and non-GAAP net income of $79 million
• Q4 GAAP EPS of ($0.20) and non-GAAP EPS of $0.12
• Q4 adjusted EBITDA of $141 million, representing an adjusted EBITDA margin of 30%
• 2014 revenue of $1,403 million, up 111% year-over-year
• 2014 net loss of $578 million and non-GAAP net income of $101 million
• 2014 GAAP EPS of ($0.96) and non-GAAP EPS of $0.14
• 2014 adjusted EBITDA of $301 million, representing an adjusted EBITDA margin of 21%
[...]
Fourth Quarter 2014 Operational Highlights
• Average Monthly Active Users (MAUs) were 288 million for the fourth quarter, an increase
of 20% year-over-year, which reflects a loss of approximately 4 million net Monthly Active
Users in the fourth quarter due to changes in third party integrations.
• Average Mobile MAUs represented approximately 80% of total MAUs.
• Timeline views reached 182 billion for the fourth quarter of 2014, an increase of 23% yearover-year.
• Advertising revenue per thousand timeline views reached $2.37 in the fourth quarter of
2014, an increase of 60% year-over-year."
Source:  Twitter's Q4 2014 Earnings press release, 5th February 2015
Earlier - 271m in Q3 2014