Imagine you are PM at Facebook. You walk into your office one day and see Messenger DAU are down by 10%. Why?

Question

Imagine you are PM at Facebook. You walk into your office one day and see Messenger DAU are down by 10%. Why?

Asked at Meta (Facebook) over a year ago

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Execution

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Chau Chu · Answer 1 · 2021-11-29T16:42:12+0000

1. Clarify the question

- What's your definition of DAU? The number of people opens the app at least once per day? Or is it the number of people open and spending time on the app at certain minutes per day? Assume that it's the number of people who open the app at least once per day.

2. Internal/External Factors

*Internal*

- Does this happen suddenly or gradually over time? Gradually over the past few weeks.

- Did we make any changes to how we calculate the metric or the way we collect data recently? No

- How about changes in product features or UI? No

- Does this happen all across platforms? Such as Mobile, Desktop or Android, iOS? The changes we saw actually happened specifically on the Mobile app.

- Does this happen on other Facebook products like WhatsApp, Facebook, Instagram? No

-> OK, my understanding about Facebook Messenger is that people can open the app by the notifications on the phone, organic open, ads, links. Since you said that the drop happened specifically on the Mobile app, one of my hypotheses is that there's an issue with notification on the mobile app which can directly affect DAU. One thing I would check is the notification received rate in Mobile app the last few weeks. If it's dropped, then I will connect with our software engineers to discuss the issue and fix the bug.

- Another hypothesis is that one of the features on the app could be broken which discourages users from using our app. I would check the daily rate of Sending Messages including the type of messages such as photo, text, GIF, message delivered and received, Calls and Video Calls. Any kind of disruption in our app features can make the drop happens gradually over the past few weeks. I would also check with Customer Support to check if there are any increasing reports about the app/features in the app.

What do you think about my answer so far? Should I stop or continue discussing other factors? Let's continue

- Next, I'd like to dive into segments of users. Does this happen only to a certain group of users? Such as New or Old users, or certain demographics? Yes, we actually the drop actually belongs to user age group 18-25.

- How about seasonality? Do we see the same drop around this time last year? Or in the past few months? No

- Is there any type of government regulations or political/global events that happened recently that we know of? No

- Are we performing any kind of AB tests related to this age group? No

- How about any recent launch from our competitors? We don't have any information on that. Any idea on how we can decide on that?

-> Yes. Like you mentioned earlier, the drop belongs to the age group 18-25, which I would assume as tech-wizard and easily targeted by competitors. In order to decide on that, there should be user behavior change. I would check user engagement metrics.

+ MAU: if DAU is down and MAU is steady then our users have become more of casual users, meaning they engage with the app less and check the app only once in a while.

+ Sending/ Calling/Video Calling Rate: if these rates also drop and continue to drop in the next few weeks there could be a chance that our users have found a replacement for Facebook Messenger and be less interested in using our app.

That's good. In fact, Signal recently offer promotions for people to download their mobile app.

Would you like me to dive into more factors and hypotheses? I think that's good, you can stop here.

Brigtaylor · Answer 2 · 2022-07-22T17:33:09+0000

Facebook DAU are down 10%

clarifying questions

Down over what time period? Just today or has this been an ongoing trend?
Are DAU down across all customer segments and regions?
Are DAU down on all devices? Mobile desktop android iOS?

Internal

Did we release any new features? On messenger or on other parts of Facebook?
Did we have any bugs reported?
We're there any outages?

External

Did our competitors release any new features?
We're there any unique events today?
Are there any seasonal factors? Does this correspond with this time last year?
Is this a daily trend? Was there a drop this day last week?

My theory is that messenger usage is highly tied to use of Facebook Marketplace. There was a bug reported on marketplace where the app was crashing when users went to message a seller roughly 20% of the time. Because messenger use is about 50% tied to marketplace conversations, the total messenger DAU metric went down 10% for the day coinciding with the marketplace bug.

Santhosh Kumar · Answer 3 · 2021-11-28T23:06:06+0000

Approach

1. Ask follow up questions to demonstrate the curiosity to understand the problem better

2. Brainstorm the root causes for a problem

3. Collaborate with a interviewer to identify a root cause

4. Recommend a solution to fix the problem and recover the metric

Follow up questions

Candidate: Is it a gradual grop over a period of time or sudden drop in a day?
Interviewer: Sudden drop

Candidate: Is it a one-off drop or presistent dip in the DAUs?
Interviewer: Do not know, the issue surfaced just yesteraday

Candidate: Do we have insights into the most affected group in terms of platform (ios, android, desktop, etc) or location (US or rest of the world)?

Interviewer: None

Brainstorm the root causes for the problem

Drivers within facebook

A) Data issue: Check whether the reporting is accurate. One way to ensure that is to check the associate metric such as #sessions, time spent, etc.

B) Seasonal: Check if it is a seasonal dip by observing the hisortical data over the recent years

C) Policy changes: Check if facebook rolled out any new policies to crackdown on the spread of fake news and misinfomration on the flatform in terms of removoing the influences that spread fake news or limiting the ability to share the news that is determined to be false

D) App upgrade: Check if we stopped supporting certain older app versions

E) New feature release: Check if there are any new product rollout that broke some of the app features such as voice call, video call, group chat, group calls, etc. On the other hand, check if the new release did not go well with certain user group that were a fan of previous design

F) Power outage: Check with there was any outage, causing the app to go down

G) Hacking: Check if there is any hacking scadal that would cause security concerns leading users to competitor platforms

Drivers from outside facebook

A) Bad PR: New privacy issues related to company practices that were released to media, causing the users to quit or pare-back their app usage

B) Browser issue/Mobile OS issue: These are critical to be able to access the message, any issues with browser/mobile os would create negative downstream impact on the app

C) App store/Play store changes: Any changes to the app store/play store algorithm might negatively affect the new download, affecting the DAUs

D) Competitors: Rivals such as snap, tiktok might release new features that caught the imagination of the public, causing people to prefer these alternatives

E) Social events: External events such as super-bowl, school re-opening woul make the users to offline and engage with activites in the psyical work, might cause the DAU go down

F) Regulatory crackdown: Countries might ban use of certain app such as messengers, as a political response. For example, coutries banning apps such as tiktok

Collaborate with a interviewer to identify a root cause

I would run these probable causes by the interviewer, and identify the main root cause. For example, interviewer might suggest that is has to do with facebook stopping to support the older versions of the app.

Solution

Given that we identified the root cause to older app versions, I would suggest to build solution where we would auto-update the older app versions to the latest version. It would go a long way to drive the DAUs up again.