Every Instagram profile has the option to tag other accounts. The post will then end up on the person who is tagged ‘Photo’s of You’ tab on their Instagram page, similar to the Facebook tagging function.
This function is most commonly used by the average Insta user who is wanting to tag the people in the pic they have chosen to upload. Another use for this is self promotion OR product promotion.
Up and coming Make Up Artist’s may tag other established make up artist’s or brands to promote themselves, just like makeupbyjack has in the picture above. As you could imagine a well established make up brand would be tagged quite a lot and may become lost in the process, but there will for sure be many crazed make up lovers scrolling past ‘posted 152 weeks ago’ i.e. me....
Of course when users see something they like they are going to want to know where they can buy that product. This is why the make up industry is quite friendly. The tagging function is great for that as well, in terms of informing their followers to stay loyal in a way.