According to Google all of the features available in iGoogle are now available in most browser and smartphone apps so it's use has eroded.
Personally, my homepage has been iGoogle for years, and my primary way of finding slashdot stories is via an iGoogle widget. While they may think that Chrome plugins will offer all of the same features, the fact of the matter is I spend the majority of my day in a corporate environment with a locked down browser. No plugins allowed. I'll likely find an alternative, but I doubt it will be Chrome, or even Google related.
For those that are unaware of what iGoogle is: