Just tried and rated it - nice little app, it's easy to get nostalgic using it
I can confirm the little bug about entering 0 and 2 of the previous poster, doesn't work right now.
Why not add an icon/function to paste the text to the clipboard? It's easy to do in the program, just 1 line of code, and like this one can also use the written text for e-mail, Twitter apps etc.
By the way, you gave the link to the US Marketplace. The app is probably available world wide; if you give the "deep link" as indicated in the details about the app on create.msdn.com the link will lead people directly to their particular, possibly non-US marketplace.