Not sure the keyboard really gives the best understanding of how a person would comment using this service. Why not show another screenshot here? It would give people a better idea of how the service works.
Overall, I think the site looks great! I noticed on the live version of the site that it is responsive, and there are a few spacing issues you need to work on there. But for this mockup, I'd mainly look at typography and whitespace. See my notes for more details.
The scrolling features attached to the mouse when it's hovering over the laptop screen is great.
People want to see the product and if the product is a web software, why not show more shots of the product. The landing page does a great job with the Attention and Interest part of the AIDA model, but I think a few screenshots or video would help to grow that desire. People sign-up for web tools like this because they get excited to use it, not because you convince them they should use it. So, I would consider adding something to that effect. You do have the "see how it works" link but that requires an added step. Instead, consider adding a teaser section below showing a few of the main features that then link to the full how it works section.
On my laptop, the 1/2/3 falls below the fold - but looking at the page you've got a lot of space between the logo and the benefits statement "Know what's..." The laptop is also quite large - again, pushing down the 1/2/3.
One more comment I came up with after using the site a bit more - the pricing info being hidden at the bottom of the page - why hide it? Instead offer opportunities to view that page and put it as a key step in your sales funnel.
I like the simplicity of the design. Clear benefit statement as well - I know immediately what this tool will do (also helps that you've got a good URL).
Reduce the whitespace and laptop image sizes
I love the whitespace, but I think you could tighten it up while maintaining the strong, open feel.
I don't know how your going to code the section with the screenshot and keyboard as your background images because these would be to separate images. I would recommend only using one image to make it easier to build out.