Finding a diary online is... very hard and few people would do it. Personally I wouldn't after all one of the definitions of diaries is that it is supposed to be something personal, not something you share.
That being said, there are plenty of places you can look at the progress of successful projects, not people. There is a catch: it won't be in a narrative fashion, rather a real world example of development.
First of all there is something you must get clear with: What are your target projects?
I will give you the answer: Only the opensource projects. You aren't likely going to find information about closed source projects, not atleast inside information which can show you the way of work and thinking.
I will give you two main examples: bugzilla and github.
What can you learn from them ? Basically how is progress made, how people communicate and you can view everything, every commit, every bugentry/fix.
A good example for a huge and successful project in bugzilla is, well, firefox.
You can find their bugzilla here, just pick a product and start reading current or resolved bugs:
The second example will be github, where you can do pretty much the same thing, but with projects of different scale. The example I am going to give is angular.js
If you are interested in up and comming projects I suggest viewing the trending repositories section:
Tl;dr: You probably won't find diaries in a narrative fashion however a lot of big projects have their development process open and you can learn/draw inspiration from them.