Google tests the ad related to recent searches in your suggestions for autosuggestion or autocomplete. I think Google will show recent searches first, followed by search suggestions based on related recent searches.
This seems like a more personalized form of auto-complete on Google suggestions than is the trend or what most people are looking for.
Here is a screenshot from Shameem Adhikarath on Twitter:
I think this is useful, what do you think?
Forum discussion on Twitter.