craftOS 1.4 has pastebin downloading by default
and yeah, you can copy/paste single lines in, but the edit program doesn't necessary work like that. the single lines thing only applies to when a user uses read() in a program.
firstly, there's not really any way to get clipboard data from lua without using read(), so keep that in mind.
basically, the edit program works by storing all of the lines in the currently open program in a table, and it detects keypresses, then appends the pressed character to the end of the line the user is on. it doesn't use read() and therefore is unable to receive clipboard data.