@Daybooks - Kudos for actually launching something. Done is better than perfect. Now on with comments that actually help the project.
Writing copy is always a pain - I still have issues with grammar and spelling, however my code is flawless :) It's a pain to proofread when you're heavily invested in the code.
The presentation is neat and clean. Until you get buzz that will do the explaining for you, it's best to put something on the front page for those who don't get what you have already. It feels intimate because you have to be in the know to have a good gist of what it does. However, it's all about your audience.
I like UI but for users with IE or older browsers, your dependence on HTML5 and CSS3 might pose a problem with adoption. Always have graceful fallback.
The images you're loading are sized way too large and take time to load. Kill the image sizes at 1080P and let responsive CSS do the rest. Faster load times and better presentation.
On the landing page or about page - show an actual example of what the daybook entry looks like. Is there a link or a screenshot?
It looks promising - is this public or private posting?