Instagram has recently allowed paid advertisements by marketers and is slowly building a business with brand marketers. The first advert ran late last year and this month it announced a deal with Omnicom, its first partnership with an advertising agency.
Deborah Aho-Williamson, an analyst at E-Marketer, said Instagram is coming on "very rapidly" and that brand advertisers see it as a "beautiful branding platform" to showcase images and video.
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But she added that the app was unlikely to take marketers away from Twitter, which is further along in the process of monetisation.
"The use cases are so different. Instagram is so much about sharing photos and video and little graphics whereas Twitter is so much more real-time information and news," she said.
Twitter has grabbed the attention of brand marketers in the US, the largest advertising market, and is moving on to other areas of the world and direct marketing and e-commerce at home. Direct response would feel "a little weird" on Instagram, Ms Williamson said.
(Read more: Turkey's Twitter ban slammed by politicians, public)
Investors worried about Twitter's user growth slowing after its first earnings announcement last month. Shares fell almost 20 per cent as analysts quizzed the management about whether growth could ever accelerate in the US. The company is busy making changes to its platform and in particular the process of joining in an attempt to make it easier to understand for new users.