Yes, we knew that and this study as mentioned by the BBC article adds to what has already been mentioned in various other news and blogging sources.
The key take away for me in this study is that content will be important to (1) get the remainder to read blogs and (2) to thereby recognize/understand what a blog is.
If what we (yes, me too) write is interesting, they will come.
If what we (yes, me especially) write is consistently intesting, they will come back.
Hence our challenge for 2005 is to be good writers!