Mayer says the figure for the 800 million Yahoo users doesn't include the traffic that the company has picked up from its $1.1 billion acquisition of Internet blogging service Tumblr earlier this year.
Despite the increased traffic, Yahoo is still struggling to boost its online advertising revenue - the main way that the company makes money. In recent quarters, Yahoo's ad revenue has been barely rising while Google and another rival, Facebook Inc., have been thriving.
Mayer says she believes it her strategy for accelerating Yahoo's revenue growth will require at least three years to unfold.
Yahoo's stock shed 29 cents Wednesday to close at $29.19.