Two traffic observations and questions

Question

The MathOverflow traffic (page views, visits, new visits) shows steady and possibly increasing activity over the last $2+$ yrs. The chart below runs from 2019-Jul-07 on the left and 2021-Nov-04 on the right. More than $2\frac{1}{4}$ years. One can see predictable seasonal variations—diminished activity near Christmas, a trough in the summers.

Two points:

• I would think that MO activity would decrease over the years, as more and more fundamental questions get asked and answered. But that does not seem to be the case. If anything, traffic is (slowly) increasing.
• Something happened around 3Aug2020.

I'd appreciate any comments/speculations that explain these two observations.

Answer 1

Is it possible that the question "Issue UPDATE: in graph theory, different definitions of edge crossing numbers - impact on applications?" might be partly responsible for the peak?

• This question now has 92k views.

• In the revision history and the timeline you can see that it became a HNQ on July 28.

• A link to this question was posted on reddit r/math on August 4: User on MathOverflow realizes he made an early crucial misunderstanding on the core content of his Ph.D. thesis 2 weeks before submission. Other users come to the rescue and he is able to resolve the issue.

• David Roberts pointed out in a comment that it was posted also on Hacker News on August 4: Math Overflow users resolve PhD thesis crisis. (I am not familiar with that site, but if he says that this will generate a lot of traffic, I am willing to take his word for it.)

• It is the question Posted in 2020 with the most views, see SEDE, search

• If we check Wayback Machine, we see 18k views on August 4 and 81k views on August 5.

If we notice a smaller peak a few days before that, that one might perhaps be connected with the question "What are the benefits of writing vector inner products as $\langle u, v\rangle$ as opposed to $u^T v$?". It had 8k views on July 21 and 43k views on July 24.

Notice that from SEDE we can get ViewCount for each question - we see CreationDate of that question, but we do not know how the views were distributed over time. Some related queries; Sum of ViewCount per day, Top viewed question per day.

On MO there are 18 questions with 100k+ views and 23 questions with 90k+ views. Here is a SEDE query showing question with the most views. I would not be surprised if you found at least some peaks in activity near other highly viewed questions. You could also check other highly voted reddit posts related to MO to see whether they lead to highly viewed questions and whether you can find some peaks in the traffic near them. (This particular reddit thread is shown as the top in the linked search, with score 2.2k.)

I would guess that it depends a bit on the size of the site and on the total number of questions per day whether a single question can significantly change the statistics for the whole site. Here are some stats from 2020 for MO. If you look at the percentage of views contributed by the top question, on MO it was in 2020 quite often above 50%. If you compare this with Mathematics in 2020, you never see a number above 30%.