That counts upon what you mean by "peak". For Jeremy Zawodny of Yahoo! (and I'm paraphrasing) its when blogging goes from being "the new thing" or "the thing that changes/reinvents X" to just another part of daily life for a bunch of people. He wants to know when you think that will happen.
My answer - and it will jar my DIY readers - just look at Xanga, LiveJournal, and MySpace. That day has already come for millions.
We may thumb our noses at those communities, but it is there you will find folks blogging as just another part of daily life.
However, I don't think we are even close to peaking in terms of innovation or in raw numbers of adopters.
