Typo "textare" in footer.

You mention creating a signature "like this one" but then the actual signature creates an ad for the service as an extra - obviously you want word to spread, but there might be a more subtle way to do that, and also disclose it in the example - a ? icon maybe?

I know it's an MVP, but you could have a few theme/style options pretty easily - different layouts, icon sets, colour schemes, etc.

Good luck.