I want to note that my response specifically deals with the messaging you
raised. I will note that the privacy of our users is of paramount
importance across the organisation and is taken seriously and with care.
You can view with Wikimedia Foundation's data retention guidelines on Meta.
Regarding the specifics about fundraising, the system that delivers banners
is CentralNotice and the tools that we use are fairly basic.  
CentralNotice notes how many times someone has seen a particular
fundraising campaign. This number is counted and kept within the web
browsers localstorage and not a cookie. This means that information is NOT
stored in the HTTP request header sent to our servers.
This feature is used for all sorts of community and programmatic banners as
well as fundraising. It means that when an individual has seen X number of
banners within their browser they don't see anymore. We wrote a blog post
about this a couple of years ago. 
All we are doing is taking the same number that is stored and using that to
note in the message. We don't track users through CentralNotice across
browsers to set messaging, nor do we track across devices via CentralNotice
to set messaging.
I will say that even though it IS privacy sensitive, the potential
perception of it is something we will need to think about and along with
the other feedback will be something we talk about as a team this week.
On Sat, Dec 5, 2020 at 7:40 PM Yury Bulka <setthemfree(a)privacyrequired.com>
In the context of this discussion, I think it might be appropriate to
share the following. A few days ago I had a brief conversation with a
(non-Wikipedian) user on social media regarding a fundraising banner
they were seeing. In their case they had an additional concern with the
banners (apart from "making Wikipedia unusable"). They wrote:
"<...> I find it more than a little creepy that wikipedia is tracking
how often I visit."
Curious, I asked if the popup said anything about their browsing
behavior, and it did (citing a snippet they have shared with me):
"Hi, reader in Canada, it seems you use Wikipedia a lot; that's great!
It's awkward, but this Tuesday we need your help. This is the 10th
appeal we've shown you. We don't have salespeople. Thanks to the
donations of 2% of our readers, Wikipedia remains open to all. If you
donate just $2.75, or whatever you can this Tuesday, Wikipedia could
keep thriving. Thank you."
We want to make the Wikimedia Sites better for you by learning more
about how you use them. Examples of this might include how often you
visit the Wikimedia Sites, what you like, what you find helpful, how you
get to the Wikimedia Sites, and whether you would use a helpful feature
more if we explained it differently.
This contradicted my intition about the privacy of anonymous Wikipedia
readers. It seems like some behavioral data is collected and then used
to target readers for fundraising in some ways.
Is it specified in more detail anywhere what kind of behavioral data is
collected, for how long it is stored, how it is associated with a
reader's device(s), and what behavioral data is used in the context of
Wikimedia-l mailing list, guidelines at:
New messages to: Wikimedia-l(a)lists.wikimedia.org
*Senior Community Relations Specialist*
*Advancement (Fundraising), Wikimedia Foundation*