People hashtag whatever they can think of on Instagram more than Twitter or Facebook. Well, Twitter is character-limited and Facebook is still pretty new to hashtags. But basically you know that anything can be hashtagged. However, Instagram does not tolerate "violent, nude, partially nude, discriminatory, unlawful, infringing, hateful, pornographic or sexually suggestive" posts.

The photo-sharing social network will go to lengths to ban offensive hashtags like curse words, or porn-related hashtags and so on from its searches, which is understandable.

Although you'll still be able to hashtag whatever you want, you just won't be able to search for the censored hashtags that Instagram has banned. So when you search for things like #fuck or #porn, Instagram won't give you any results. They'll just take you to a page that says "no tags found."

But the strange thing is that Instagram also banned these 10 ordinary, inoffensive hashtags:

#iphone4s (#iphone5 is not banned from searches)

Apparently, the reason these tags don't exist to Instagram is because they're too generic. According to Instagram cofounder Mike Kreiger:

“We’ve stopped serving feeds (both in app and API) for some tags that were too generic and didn’t provide enough end-user value.”

Well at least you'll know not to waste any time hashtagging these things now.