Why should I blog (or write a diary)?

Lets have a look at the benefits and drawbacks of blogging. There's a small difference between blogs and diaries: the former is public and the latter is private. Looking at it from the 'how-can-I-earn-money-oline-perspective" it's a huge difference, but the process that the author is going through is very similar.

Benefits:

• Reflection: you are forced to think about your progress and what you would like to achieve.
• Practice your writing skills.
• You'll be able to go back later if you can't remember what you've done (not needed if you use some software like mercurial, subversion or openUP, but I guess usually it's overkill for small projects, means the overhead is bigger than the reward)
• Blogs may also get valuable input from readers.
• Blogs may also earn you some money (Anne Frank's diary made some money too, but not for her, a tragic story)

Drawbacks:

• You have to invest some time, that you could use otherwise.
• It can be depressing if you focus on the things that went wrong, however it's also good to reflect about why something went wrong.

Conclusion:
In my opinion the benefits you get from reflecting about your work outweights everything. Everytime you write about your project you'll automatically update your plans. You'll be more flexible and adjusted to the latest developements. You'll probably also notice faster if you're running towards a dead end or running in circles. So blogging could actually save you some time.