Facebook is now allowing you to view the IP address, general location, device name and type, and web-browser version for the last several people/devices that have accessed to your account. This is in addition to the Facebook "named device" security feature. This IP activity feature/service just started this morning and is activated by default. To view what IP's have logged-in to your Facebook account look under Account Settings and click "account security". You should see this new IP & login information listed under "account activity".. Hover your mouse over the "location name" to see what the IP address is. You can also "end" the activity (but I'm not sure yet what that does). Note that the location of the IP address is very general. You can type the IP address into a service like http://whois.domaintools.com to get a better IP location.
As Trinity and Hubby both correctly pointed out, it was not suggested this new feature had anything to do with anyone viewing one's page.
At the end of April, the "name this device" feature was added under Account Setting - Account Security. If one chose to participate, upon logging on they would see this:
After naming the computer an email would be automatically sent to the email on file with FaceBook. If one logged in from a mobile device - the mobile device would NOT see this screen but would still be logged in this area and an email would be sent.
Yesterday morning, a new feature was added under this same setting (Account Security). It shows IP address, the approximate location - so far it's very approximate - OS/Computer and the time of the visit.
Unlike gmail, it does not keep a running tab of the last five login IP addresses. It is actually showing the current login information. In other words, unless there is another computer logged in* you are not going to "catch" someone who was previously in your account because that information gets knocked out once you login and are viewing it.
*Only once has it shown another computer logged in for me. It was when I left my home computer logged in and signed in from a friend's house. It then gave me the option to remotely "sign out" the "other" machine = my home machine.
We have been trying with different computers and mobile devices (but at the same IP) to "catch" someone in the account but it doesn't seem to work. All the people I trust to be in and out of my account are under the same roof.
I decided to try with a proxy server from one computer while another computer was signed in from our real IP.
WARNING: Using a popular free site that "hides" your IP, I logged into my daughter's account. It used an IP from the UK and sent a red flag to FaceBook. FaceBook then required us to verify the account the next time we logged in. It did so by showing 7 tagged pictures of 7 "friends." It gave a list of about 6 names and we had to correctly identify the "friend" by the photo. NOT AN EASY TASK!!! Some were baby pictures or pictures that had been photo-shopped into monochromatic green, gorillas tagged as people, etc. It allows you to "pass" twice but after that if you don't guess right ... you are SOL for an hour and then you can comeback and do it again. We were more successful the second time and we were asked if we recognized the "offending" IP address in the UK. We said yes - but I wonder what happens if one says no. I'm sure FaceBook would require you to change your password.
I'm suspicisous so I wonder if this is a sneaky way to hone any photo recognition software by training it. Additionally, what happens to businesses or people who have 100s of "friends. No effin way I could have done that with all the photos 100s of people have on their FaceBook accounts. It was really annoying. Not a feature I was thankful that they added AT ALL!
Perhaps someone else can give it a few test runs and report back.