When I have an aviation "general subject" question...
I simply take my computer and click in "www.google"
first...!
As an example - google gives "Boeing customer numbers",,,
That directs me often into
second - the criticized but excellent "Wikipedia"...
Funny is, you can even put the question in a few languages too.
I have seen Wikipedia making errors, but it is rare, aviation or other subjects.
And then, if that still does not work,
third - I finally type the question on Pprune.
This avoids the famous question "what is...?" -
Followed by 10 to 20 answers that could be replaced by a short one.
And then an idiot like me suggesting "google" or "wikipedia"...
How simple life is, for some of us... but takes years of life experience...!
xxx
Happy contrails
P.S. I believe the Boeing customer number listing was requested many times in our forums.