For example the SN sections. I realise they still exist, and completely understand and support why they are hidden, but the way that it used to work was that they are automatically hidden from Active Convos, but if you wanted to be able to see them in your own Active feed, you could go to Customise and enable them. It worked like this for years and it was a good system. Parents interested in SN topics could access them just as other threads, and posters with no experience or interest did not come across the threads by accident and post well-meaning but unhelpful replies or sometimes downright hostile ones, which is what (I understand?) happened before the topics were hidden.
It no longer works like this, not sure since when, certainly several years, possibly one of the big redesigns. Now even if you opt in to see them in Customise (or Talk Settings is where it is now), they never appear in Active, they are always hidden. In fact there is not even really an opt-in option any more, just "unhide" (but my unhidden SN-related topics don't show up in Active anyway).
This IME makes it really difficult to participate in discussions there. Partly because of my own ADHD - I tend to forget to check the sections manually, but also because it means that if you do start or respond to a thread there it rarely gets many replies because it's not being shown to anyone who doesn't manually go to each of the SN sections and check them fully. I have a sort of workaround which is that I subscribed to all the topics which act like this that I'm interested in, but even with this, that means that I have to go into the My feed section to see them as a sort of annexed off Active Convos.
I have just seen in chat that there is a new SEN support thread posted there and the OP states that she chose not to start this in one of the SN sections because she thinks most people are unaware that the SN sections exist. And it's true, most of the chat threads in the SN sections are visited mainly by "old hands", MNers who have been here since before this change happened. Obviously I am totally in support of posters running whatever support threads they like wherever they like, but I just mentioned it because it seems a bit of a glaring design flaw with the way that hidden-by-default topics currently work, that someone wanting to offer a supportive space to others interested in that topic has to do so in a non-hidden area of the site otherwise nobody can find the thread. The SN sections used to be really busy and a massive source of support for a lot of posters, but now they are like a ghost town.
With a lot of anti-SEN sentiment on the more general boards at times I also wonder whether this is part of why certain posters feel that "every other thread is about SEN" if posters no longer are generally aware of or have access to these sections.
In fact, I have just used Advanced Search to do a sort of little survey and these results are pretty shocking. I searched for any posts in SN Children within a certain time period and narrowed this down until it got under the 2,500 max result threshold (which was a week in 2008, BTW), changed to March rather than January to avoid New Year posting slump and these are the results from 1st March-7th March, each year from 2008-2021. The change you can see must have happened between March 2014 and March 2015.
2008 - 966 posts a week
2009 - 1541 posts a week
2010 - 1079 posts a week
2011 - 1349 posts a week
2012 - 1533 posts a week
2013 - 2500+ posts a week
2014 - 1530 posts a week
2015 - 466 posts a week
2016 - 262 posts a week
2017 - 296 posts a week
2018 - 113 posts a week
2019 - 151 posts a week
2020 - 118 posts a week
2021 - 129 posts a week
I am going to crosspost this in AIBU for visibility because I honestly didn't expect to see such a gigantic drop off and find this really upsetting that it's been ignored by the site staff, who presumably have access to these kinds of posting numbers more easily than me running manual searches, when the topic was such a brilliant source of support for so many posters previously.