Reality seems to say multiple competing XML formats for content syndication existed around the same time. Someone took some features of Winer's format and combined it with an existing one and called it RSS. Shrug
And on inventing blogging I read up thanks to wiki [1], as usual, and lo and behold! The claim his blog is one of the oldest is sourced! To an interview in which he claims it about his own blog, and then discounts it a sentence later.
I have no opinion on if this guy actually influenced as much of tech history as he seems to think, but history has either been very unkind to him, or he promotes himself beyond the facts.
http://www.rssboard.org/rss-history
Over time, the number of Internet technologies Dave Winer didn't invent approaches zero.
The term "blogging" came a good time after this.