Twitter Inc. said on Thursday it could turn its first ever profit in the fourth quarter, after making sweeping cuts in expenses the past few months and finding sources of revenue beyond the advertising that dominates social media.

San Francisco-based Twitter also disclosed in its quarterly earnings report that it had discovered an error in the way it had calculated the size of its user base since 2014 and revised its estimates downward, but that the difference amounted to less than 1 percent.

Twitter reported third-quarter revenue of $590 million, down 4 percent from $616 million a year earlier. The company attributed much of the decrease to a previously announced decision to wind down its TellApart advertising product.