So out of curiosity I looked to find the first post. It turns out that the first post was on December 26--not as an introduction to the blog, but rather a chart of the rockets and mortars fired on Israel during 2008.
The very next post is the next day, December 27, giving the IDF Spokesperson Announcement that Operation Cast Lead against Gaza had begun.
So it seems that among the many things that the IDF did in preparation for the operation in Gaza and to insure its success was to start a blog.
Looking back, when the IDF came out with a blog on December 26--and remember we are talking about Israel, which is not know for its PR prowess--everyone should have known that something was up. In addition, the fact that the very first post dealt with all of the rockets and mortars fired by Hamas on Israel should have been a clear warning to Hamas that then was the time to go hiding in their underground bunkers.
In retrospect, it all seems so obvious now!