As for the URL - well, I'm not really into making a micro ISV/SEO-blatant site.
Facebook sign up - I really should have that.
I have personally never clicked a landing page video. I think the only example I know of it actually being a good decision is Dropbox. I want to see a description with images and text (something my page lacks, really).
2. Having a good url is a form of communication, or branding. It took my over a minute to understand what your site was — people start with the name of the site and work their way down. If you hear of a url and don't get what the site is off the bat you've failed before you've started.
3. You need to learn what your personal preferences are don't matter — so while geeks may like pictures and text normal people might not. Geeks loved MS-DOS which is why Windows conquered the world...
2. I get your point, but are you talking about choosing something like achievergradetracker.com for the primary URL?
3. You have another good point, however I think that personal preference is more important than people admit. If we didn't infuse some personal preference, especially for aesthetics, into web design the whole web would look like fucking infomercials, which probably convert like Jesus. I guess that's kind of irrelevant as a video walkthrough is really something I have no good reason for not trying.
2. That url is terrible — you need the words "grade tracker" in it: http://www.wolf-howl.com/seo/how-to-choose-a-new-domain/
3. You should allow a signup via Facebook (especially for college kids)
4. Maybe have a simple screenshot video instead of those stills?