I took a look! But it seems the target market is teenage girls. Maybe I need to configure it, but why? Between reddit, imgur, pinterest... Really what's the dif

I took a look! But it seems the target market is teenage girls. Maybe I need to configure it, but why? Between reddit, imgur, pinterest... Really what's the difference? How many profitable image sharing apps can the world actually support? I'll admit I didn't spend much time on the site (simply because all the images I saw were of cute boys) but I failed to see the differentiator or innovation. What's the original idea here?