There are many use cases of machine learning. Recommendations are the first such examples. Recommendations for friends by facebook and products recommendations by Amazon are few examples.
Categorizing news articles into predefined groups such as Satire, Political, creative etcetera is a tedious task and it can automatically be done using machine learning to a very large extent. Google news is using machine learning to group together the similar news.
Given a corpus of text identifying the key topics is a very important and difficult task. Such task can be accomplished to a good extent using machine learning.
Given an image identifying various objects in using is called Computer Vision. Machine learning is being used to a very large extent in computer vision in order to identify objects in it.
Natural language processing (NLP) is a field of computer science concerned with the interactions between computers and human (natural) languages, and, in particular, concerned with programming computers to fruitfully process natural language such as English. Lately, there has been a huge progress in NLP using machine learning.
The other examples are:
Find Similar content based on Object Properties
Detect Anomalies within given data
Ranking Search Results with User Feedback Learning
Classifying DNA sequences
Sentiment Analysis/ Opinion Mining
Speech and Handwriting Recognition