Regular users can see a recent list of who has been spying on you, along with some basic analytics, while paid users can see up to 90 days worth of viewers, as well as more detailed analytics.
From my research it appears to take into account recent interactions (in messages, chat, or comment threads) and frequency of recent chats.
It's rumored across the web that the person located at the very top of your "Initial Chat Friends List" is the person who last looked at your profile, but this is wrong.
People you never have contact with will most likely be at the very bottom, and those that you communicate with more frequently will probably be up top.
For me, the first three profiles that showed up were with people that I messaged or chatted with yesterday.
To substantiate my claim that this does not show people viewing you, I had my roommate check out my profile about 25 times in an hour.
I went back in to check my list, and it remained unchanged.So, it most definitely does not prioritize people checking out your profile at the top of the list.But still, it's a fun way to check out who you have contact with most (though, you should probably already know that).If you'd like to view it for yourself, you can easily find this list by viewing the source code of your profile page.To do this, just go to your profile page, right-click in an empty area on the side, and select "View Page Source." This will you show the page's source code.From here, go ahead and press Command+F (Mac) or Control+F (Windows) to open the find feature.