Backstory: Every time we make significant changes to a marketing funnel, I annotate Google Analytics so I have some sense of historical knowledge when tracking conversion. I've been taking screen shots of the pages and uploading them to drop box but it's often out of sync and not organized.
The Idea: Historical marketing funnel cohort analysis.
Deep Dive: You would build a simple platform for a user to create a "marketing snapshot." This would involve crawling every sales page and take a screen shot and grabbing conversion analytics. You would have to integrate with google analytics or something like baremetrics.
Validation: When chatting about this with a friend, he pointed me to this: https://github.com/BBC-News/wraith. It's essentially what I'm looking for except it involves a lot of manual configuration and management. There's a space here for a SaaS tool to manage all of this.
Monetization: You would have a typical SaaS model, charging per seat and feature set.