Regarding point 1 - this is definitely something I've been thinking about too. For the MVP, I have the job poster supply an outbound link to their current job post/resume collecting portal. But, my plan is to build an application screening component into the site as well. For the applier, we can save their information and allow for frictionless applying, and for the recruiter, my hope is to put things in place where they can better filter their candidates so it's not as overwhelming for them to review candidates.
2) I think you're right that I should add a "last X daily jobs" so people can browse if they missed the job of the day. But, my hope is that having a super narrow focus (entry-level marketing jobs at top tech companies) means that the job relevancy goes from 1 in 10 to maybe 1 in 3. Similar to Woot.com or any daily deals site, the deal might not be relevant to you today and that's okay. It's so easy and passive to just come back and check tomorrow if there's relevance that I'm hoping to turn this into a more passive, DAU heavy product than traditional job boards.
Regarding tracks, 100% agree. A lot of people I've shared the idea with say I should create things like "/developer" or "/finance", and I do want to do that in the future. But, for now, I'm sticking with a very narrow focus because I've seen how a broad target results in poor engagement from many users whereas this time I want to have heavy engagement from a small subset of users.
Keep the feedback coming!