Oil Filters????

Are all oil filters the same? A couple years ago I picked up a Fram oil filter for my Dodge Dynasty that I used to have. I bought the filter to change the oil then the trans went so I got rid of the car. I had the filter sitting around and thought I would try it on my Dart and it was a perfect fit. There both idenitcal beside the writing on it and the model numbers.

Since it was a Dodge to Dodge filter I guess the chances are pretty good that it would fit but are the threads the same on all cars? Are the internals designed differently for other makes and models? I never noticed this or thought about it until I used the oil filter I had sitting around. LOL! Been changing by own oil for quite a few years now!!! LOL! and just thought about it now!