The following excerpt was extracted from the FAQ.
What are admirers?
Admirers are people who receive your Fun. If someone admires you, they're your admirers – they'll receive your Fun in their homepage. If you admire someone, you are their admirer.
What is admiring?
Admiring someone on 9GAG means you are subscribing to their Fun, and their Fun will appear on your 9GAG homepage. Your admirer/admiring stats are listed on your profile page.
If I understood it well I can have a page fed with customized content. I've looked everywhere and couldn't find a 'subscribe' button or where in my own page I'd see that. How do I become someone's admirer?