As someone who used to use Twitter a lot, it is definitely noticeable.
I joined Mastodon back in April and it's been refreshing, none of the bitterness that you would normally see on the birdsite is visible.
However over the last week it has been evident that his takeover has had an effect - in that my timeline has definitely slowed down. It used to be really busy first thing in the morning or in the evening UK time, but it's now like a ghost town (hence the title).
From what I can see, mainly from the daily email/spam of whats been happening, of those new accounts, they seem to be porn bots. Before it used to be handy seeing 6 tweets I probably missed over the previous day. For example this morning's email is 2 useful tweets & 4 scantily clad images which I don't want & could get someone in trouble if they opened it up in a work setting.