The spokesperson didn't name specific websites, but upon checking, we can confirm that Instagram continues to support Twitter, LinkedIn and, of course, Facebook links. If you try to add a Telegram or a Snapchat profile, though, you get this message:
Telegram founder Pavel Durov took to Twitter to air his grievances against Facebook, IG's parent company. This isn't the first time a Facebook-owned service put up walls keeping out Telegram links, after all: in late 2015, Whatsapp also removed the ability to deeplink to its rival messaging app. Durov believes Facebook has been targeting his service either because it's been growing steadily (he says it now has 100 million monthly active users) or because of the launch of its public chatrooms called Channels, which could make Telegram a legit social network. We've reached out to the Snapchat team for their insights on why IG also blocked their ephemeral messaging app, and we'll update this post if we hear back.