If you visited Google in the pass, there was a link at the top right that said something like "Personalised page". It allowed you to personalise the google page, by adding things like clocks, calenders, notes and other gadget type things. You could switch between classic and personalised page.
Now they've renamed it as iGoogle and added some new stuff like backgrounds and things I believe. So if you have the personalised page, you'll see the iGoogle logo. If you have the classic page, you'll see the original Google logo.
This is actually really quite cool... I thought this was going to be one of those sad phases things which no one would use - but I'm setting this as my homepage instead now
"Oh right, iGoogle is Google's attempt to imitate Dashboard."
Don't think so - iGoogle has been around for the last 1-2 years I believe, it's just changed names from Personalised home to iGoogle. And I think iGoogle and dashboard are quite different.