Usability, as the term indicates, refers to the ease of use of an interface. I took a look at Facebook’s mobile app to see how it measures up. Verdict? Interesting.
I’ve used Facebook for over a decade now, and it’s been through some major changes. I don’t remember the changes themselves at this point, but I do remember noticing them (and not always happily). We don’t respond well to change, especially when what’s being changed seemed to be working just fine before the change.
With the advent of smartphones, enter Facebook’s mobile app. It was a natural extension for a popular platform, and I took to it easily. It was quickly learnable and it operated efficiently.
After years of using Facebook daily, whether it be on the website or on the mobile app, I stopped a year ago. It was sudden and unexpected, with really no reason behind it except that I just didn’t feel like using the platform anymore.
Recently, I began using Facebook again to connect with hobby groups. The website was as I remember, and it felt like a familiar trek into a familiar land. When I opened up Facebook’s mobile app, however, I was jarred. It looked different, it felt different, and I felt different using it. I considered myself pretty experienced, if not rather skilled, in using Facebook and mobile apps in general, but this felt unfamiliar to me. In particular, I wasn’t sure what the tab buttons at the top of the page indicated until I clicked on each one.

When evaluating usability, I consider Learnability, Efficiency, Memorability, Errors, and Satisfaction (LEMErS, for short). For this app, I will discuss mostly Learnability and Memorability.
Learnability: how easy is the system to learn?
Facebook’s mobile app doesn’t hide anything — you scroll down the page to see content just as you would on the website. Affordances like the highlighted tabs along the top of the page also indicate what is being shown: right now, the homepage icon is highlighted in blue, indicating that the user is currently looking at the homepage. If you want to comment or like a post, these actions are clearly labeled and easy to figure out. Overall, there is consistency across every app page in regards to text, labeling, and layout. All of these factors contribute to the relative ease of use.
Where the app fails for me, however, is consistency across Facebook’s app and Facebook’s website. Hey, I’ve used Facebook for over a decade and still didn’t recognize what these tabs were:

In case you didn’t know either, the first tab to the left is Groups, and the one next to it leads to the Marketplace. To my knowledge, I haven’t visited either of those pages frequently on Facebook’s website, and so I didn’t recognize the icons on the mobile app. I also tend to navigate Facebook’s website by reading the text next to icons rather than depending on the icons themselves. On Facebook’s website, the Group tab and Marketplace are in completely different categories along the side of the page. I never would have recognized the icons because they weren’t pages I regularly visited, nor would I have expected the two to be next to each other.

Because these tabs were the main navigational tools on the app, I felt immediately thrown upon opening the app. It’s a small thing, really — and quite easy to learn once you click through the tabs — but, as a longtime Facebook user, it was jarring.
Memorability: does the system effectively reduce a user’s memory load? Does the system allow for a returning user to easily reestablish proficiency?
I was a returning user to Facebook’s mobile app. It was easy to figure out what I was doing, but it took some exploration. I also want to point out that it took some time before I actually remembered what the top tabs were — I had to click through them every time I opened the app the first few times. Even now, if I don’t use the app for a while, I have trouble recalling what the icons stand for (granted, I have an exceptionally horrible memory and probably can’t blame Facebook for this one).
I also thought it was interesting that the mobile app displays different navigation tabs for different people: the Facebook app on my husband’s phone, for instance, doesn’t display the Marketplace icon but instead shows the Videos on Watch icon. Now, I’m assuming that this difference is based on some sort of user analytics, but I find it strange because I never actively used or visited Facebook’s Marketplace, whether it be on the website or the app. It also brings up the question: will the tabs change over time if my Facebook habits change? Will I one day open the app and find completely different navigational top tabs?
To bring this all together and finish off this post: Facebook’s mobile app is easy to learn and to use — especially if you’re a regular Facebook user. I question, however, whether the navigational tabs accurately reflect the user’s preferences and are intuitive enough to display only simple icons. I personally would have expected to see the Groups tab and Marketplace tab under the slideout menu to the right rather than being displayed in such a prominent place. While these are relatively minor issues and don’t exactly hamper my use of the app, I have to wonder whether it would perhaps be a good idea to more closely reflect the organizational structure of Facebook’s website in the mobile app.