Note: this question is an edited excerpt from a blog posting I wrote a few months ago. After placing a link to the blog in a comment on Programmers.SE someone requested that I post a question here so that they could answer it. This posting is my most popular, as people seem to type "I don't get object-oriented programming" into Google a lot. Feel free to answer here, or in a comment at Wordpress.

What is object-oriented programming? No one has given me a satisfactory answer. I feel like you will not get a good definition from someone who goes around saying “object” and “object-oriented” with his nose in the air. Nor will you get a good definition from someone who has done nothing but object-oriented programming. No one who understands both procedural and object-oriented programming has ever given me a consistent idea of what an object-oriented program actually does.

Can someone please give me their ideas of the advantages of object-oriented programming?