This likely comes as no surprise to anyone, but when you search on your desktop vs smart phone vs feature phone, Google will give you different results. For the most part, I think the desktop results are very similar to the smart phone results - depending on the nature of the query. But feature phone results can differ greatly.
A WebmasterWorld thread says not only do the results differ but the number of the results displayed differ also.
It is known that Google has a different index of sites for feature phones but it is my understanding that the same index is used for smart phones and desktop users. The search results may change based off of Google determining intent of the smart phone user differently than a desktop user - which makes sense, but the index I believe is the same.
So why would the number of results be so drastically different between desktop and smart phone search? My tests didn't show a huge difference in the number of returned results between the two. So maybe it is a test or maybe it is a bug? I am not sure - but we do know Google added a new mobile bot for smart phones, so maybe Google is building a special smart phone index?
I did run one additional test, a search for umbrellas:
|Web Desktop Results||Smart Phone Results|
Bryson Meunier posted a nice report on Influence of Mobile Sites on Google Smartphone Search Ranking. Worth a read.
Forum discussion at WebmasterWorld.