I believe the most successful venture of Microsoft has been Microsoft office. I think that is the software program and product that is probably the most popular for both companies and for personal use. I believe they have probably made the most money off of Microsoft office. It is expensive and when you buy a new computer you most likely need to have it installed in order to do any type of documents or presentations.
There are other software programs out there that are for eat are much cheaper but some people get used to the Microsoft office and so they have to purchase that in order to create documents and presentations easily. Microsoft has had other successful products but I believe office is the most successful.