The main selling point of Instagram is its lack of links, which is why many people use it regularly. The USP (unique selling point) conveys to followers why they should follow your profile. If it allowed links, it would likely be filled with spam posts and not attract real users. In the past, it did have links enabled, but only a limited number of people used them frequently. Stumble Upon, however, stopped functioning as it sought to increase profitability.
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