You're onto something: Very early blogs around the millennium where often build around very short paragraphs; not big articles. Take a look at these; if one squints those looked far more like later Twitter streams:
Then in the early 2000s blogging resulted in a style with longer articles instead of paragraphs. In the middle 2000s a "retro" style begun with far shorter and differentiated entries, the so-called tumblelog:
https://web.archive.org/web/20020603092331/http://www.kottke...
http://scripting.com/2001/09/11.html (Every paragraph is in effect an "entry")
Then in the early 2000s blogging resulted in a style with longer articles instead of paragraphs. In the middle 2000s a "retro" style begun with far shorter and differentiated entries, the so-called tumblelog:
https://kottke.org/05/10/tumblelogs
The original Tumblr may have been inspired by this, if not just the name.
And then Twitter and other social media arrived on the scene and ate everything. :/