Twitter also intends to implement a form of quality control on its tweets, highlighting those that are of a high quality, and hiding those that are unhelpful or abusive. The end result should be that longer threads are more relevant and more noticeable.
Of course, there is such a thing as free speech and these moves by Twitter will inevitably be seen by some as a means of quashing that free speech. However, the point is that these tweets that are potentially unhelpful, uninformative or offensive won't be removed completely; rather, users of Twitter will be able to exercise more control over whether they see them or not.
The question is will Twitter silence abuse, and what effect will these measures really have? The next few weeks should tell, as these changes and others are implemented gradually.