Well - it's considered as nice behaviour, to post the solution to a question, even if you made the question yourself. People could find your question by searching the web, and finding a remark 'I found the solution' will not help them.
If you mention your solution, others may benefit. Else it's a waste of time. The sad truth is: nobody is really interested, if you (or I) find a solution. They have their own work to do.