Rival social network Facebook to post earnings changes to advert model.
Twitter saw a 9% decline in its stock on Monday after a fall in one measure of user engagement during its third quarter.
Timeline views per user on the social network fell by 7% worldwide to 636, while 181 billion timeline views globally also disappointed analyst expectations.
Nate Elliott, an analyst at Forrester Research, said: "Twitter simply hasn’t changed much over the past nine years.
"While it has enormous notoriety, that hasn’t translated into an enormous user base. If the company can’t get more people engaged with its site more often, marketers might shift their focus elsewhere."
Monthly active users of the social network continued to rise by 23% to 284 million, a point less than the previous quarter, while revenue exceeded expectations by doubling to $361m in the third quarter.
The new comes before rival social network Facebook posts its earnings at the end of trading on Tuesday, amid changes to the way it handles advertising.
"The company has increased the size and reduced the quantity of its ‘marketplace’ ad units," Elliott said. "It’s also testing the video ads many marketers crave."
He added that marketers had last year told Forrester they were "significantly less satisfied" with Facebook ads compared to paid search, email marketing and regular banner adverts, but that he expected the company to continue to increase its revenue even so.