Feedback is very important for an author. To be honest, it's one of the main reasons why we write at all. And it's the only reason to publish a story: To find out what others think about it.
If you've read a story, just take a minute and drop the author a line. Tell them what you liked or disliked, and why. It doesn't only make us happy, it also makes us better writers.
Apart from this, you are doing it for yourself, too. Because if we don't get feedback, we might lose interest and stop writing, or at least stop publishing what we wrote. And that would be bad for everyone, so please don't forget to send feedback - always! This can be done very easyly as stories on the web always have a link to eMail the author. Just click on it and drop a quick note.
Thank you very much!