I've been doing this for several years, and it doesn't seem to reduce the number of ads I get. I just start getting absurdly irrelevant ads. A memorable one was for @7Up_Nigeria. I live near NYC.

>I just start getting absurdly irrelevant ads.

I'd count that as progress as they are easier to ignore. The ones I don't want are those that are relevant enough that they might prompt a change in my behaviour.

Anecdotally, this strategy does not work on Reddit: I've blocked u/madebygoogle and still get shown ads by that user account all the time.

Gonna try it on Twitter though since you say it works...

Is that a list that can be easily exported/imported?

I don't think so, which makes my account more precious :)