Hacker News Reader

I would think that as long as you're not distributing the font file you should be fine. If you want to be safe, go for fonts that are distributed free, and provide credit somewhere on the site.

If you stick to free or standard fonts, I think the worst that happens is that you have to take them down, especially since you're not charging for use.

And whatever you do, don't use comic sans (http://bancomicsans.com/home.html).

Adobe would rather you didn't know, but fonts can't be copyrighted.

For the button, just manipulate the 'href' attribute of the download button the same as you would update the textfield value.

I would guess that embedding any font is legal, as long you're rendering it and not distributing the font file.