TEI is the acronym for the Text Encoding Initiative and is a set of guidelines and tags for encoding texts in the humanities. You can find more information on the initiative’s website.
TEI includes a verse module that specifies guidelines for encoding poetry. On end/line, you can use tags from this module.
Yes, you will need to know some TEI to use end/line, but, because we envision this site as a pedagogical tool, we hope that you use it both to learn and to practice TEI.
Yes, you may only upload poetry in the public domain, per the Terms of Service. At the moment, however, there are no other limitations.
Yes, you may search the site for already-uploaded poetry that you are free to encode.