Numbers, numbers, numbers

This story finally reached Australia: Ghosts of blogging haunt net cemetery The Australian reports:

"Lohan's blog has since taken its place in the internet's fastest-growing graveyard - of an estimated 200 million blogs that have been started, then abandoned."

Here's the source for the story: Bloggers: All Typed Out? which reports:

Are you a blogger? if so, you're in good company. Blog search engine Technorati pegged the number of active blogs at around 56 million this past October. By January 2007 that number had grown to 63.2 million, with 175,000 new blogs begun each day.

Sounds like a big number, but it turns out that the graveyard of the blogosphere is even bigger. Half of all new bloggers abandon ship within three months, Technorati estimates. And last December, research firm Gartner calculated the total number of dead, abandoned blogs at more than 200 million. Gartner went on to forecast that the total number of active blogs would peak at 100 million in 2007 before dropping back and leveling off at around 30 million.

Here's my question: 200 million abandoned blogs? Where did they get this numbers from? I can't find the original source.