Could someone underline the advantages of Google Reader and the features that will be missed ? What had it that other free products don't ? (I use a desktop re

Could someone underline the advantages of Google Reader and the features that will be missed ? What had it that other free products don't ? (I use a desktop reader for news (FeedDemon) and an Android app for podcasts, I don't really know what I'm missing by not using something like reader.)