I think your product looks really cool, but doing a 30 day trial on a product like this doesn't make sense to me. I may not even be able to validate the products usefulness in 30 days.
What I would suggest is that, as a marketing professional, I have a TON of topics I'd like to monitor. Why not let me monitor 1 topic forever and then force me to pay if I want more?
I guess I'm more interested in why this isn't a freemium product. What was the thought process?
The reason we haven't pulled the trigger on this to date is twofold. First, we're a bootstrapped startup and we've been cautious about our burn rate (e.g., scaling infrastructure before we've achieved product/market fit and a sustainable revenue model). Second, for some time our product wasn't fully self-service. We were concerned about the support issues that would come with a significant growth in our user base, especially free users, potentially outside our target market.
We've now progressed beyond these two issues, and will launch a freemium model soon, with 1 or 2 interests and cached results that are updated once or twice per day.
I'd appreciate any other feedback, and happy to answer questions by email at mjfern@intigi.com.
I'll share some details of how we weathered the support issues :).