Twitter advertising revenues in 2013 hit $594.5m (£355.4m), a year-on-year increase of 121 per cent.
Meanwhile, growth in ad engagements hugely outpaced revenue, increasing 708 per cent – meaning that average cost per ad engagement dropped sharply, down 68.8 per cent on the previous year. However, ad revenue per timeline view increased 43 per cent year-on-year.
“The decreases in cost per ad engagement over these periods were primarily driven by higher ad engagements as a result of continued improvements made to our ad products and our prediction and targeting capabilities,” reads Twitter's annual report.
“This reduction in cost per ad engagement made our Promoted Products more attractive for our existing advertisers and new advertisers, including small and medium sized businesses with smaller advertising budgets, as well as international advertisers.
“As we continue to optimise for advertiser value and the overall user experience, the cost per ad engagement may continue to decline over time, and we expect the cost per ad engagement to decline in the near term.”
Twitter's net losses in 2013 totalled $645.3m, more than eight times its losses the previous year ($79.4m).
Mobile is one of the brighter spots in the report, accounting for an average 76 per cent of monthly active users. More importantly, ad revenue kept pace, with mobile making up 'over 75 per cent'.