According to some, it's a way of Google looking at your site but not really including it in the index, while it's new. It's a preventative device to stop people opening up domains and filling them full of cr*p.
According to others, it's a way to excuse the fact that their new site hasn't got as many links and pages as the sites they hoped to compete with...
You can choose whether you believe it's real or not!
The REAL evidence is rather patchy.
A polite name for this month's upheaval when Google changes which pages are in the index, which are important pages, and which ranking methods seem to have changed.
Each year we see updates with different letters of the alphabet...
or so some people here would have us believe.
Some of us rise up at every update, some slide down, and the result is always a baying contest between the losers who don't know why, and the winners, who don't care.
You may be a newbie, but stick around - it's VERY funny to watch!