Onetab export format to gists;

_onetab_export_markdown.bookmarklet.js

// works on selected text
var selection = window.getSelection().toString();

if (selection) {
  selection = selection.match(/[^\r\n]+/g)
    .map(function(a) { return "* " + a; }).
    join("\n"); 
    prompt("Here's your markdown:", selection);
}