Just some hopefully constructive feedback here: for Excel power users, you're not just competing with Excel, you're competing with Excel+ODBC+SQL+Workbench which is basically an Excel/DB hybrid, just not web based. I read your "how this is different than a spreadsheet" blog, and none of the examples struck me as compelling, even though I use my Excel/SQL toolchain every day. Given how strong the ecosystems are around…
One big point that we forgot to mention in that blog post is that Excel is hard to work with when multiple users are involved. It would be quite a bit of trouble if Excel users want to implement access control on whether some users can read or write certain entries.
This more closely mirrors the workflow in my office at least, where only a handful of people create reports, but maybe 10-20x the number of people just want to consume it.