I might be alone in this, but I absolutely hate landing pages like this. Your copy is absolutely correct: it IS a bait and switch.
I was ready to pay for the app to try it out, and now I can't give you money? I understand the data you could gain from this is valuable, but is it really worth it? I'm not going to throw my email address to you for an app I'm mildy interested in trying, especially after that.
Gmail solved (mostly?) these problems for me: you can mute conversations (archive & automatically mark new messages as read) from the dropdown menu on the inbox screen.
It's a neat little device. I bought mine probably a year or so ago and it's sat largely un-used. I think they were fairly new when I got mine, so these issues might have been fixed, but...
1) small size (think mine's 7 inches or so?)
2) difficult/impossible to write small enough to fit a good amount
3) no way to save pages (in any way). I tried to hack my way around this by snapping pictures of full pages, but it just became too much of a hassle.
Even if you have no real interest in C, check out K&R if you haven't. It's a near flawless (imo) example of technical writing and language introduction.
Mr. Norvig has been a huge inspiration to me ove the years. I sent him an e-mail a couple of years ago with a quick question. He responded within minutes, and as a young lad, that was huge.
It's really inspired me to try and become someone who not only writes and creates brilliant things, but also helps to foster that same ability in the younger generation.