If you really want to re-enable blink tags, drop this in. It's terrible code, but it is also tweetable. Besides, if you are using blink tags, who cares about a few global variables?

Example: http://ryanrussell.me/404

    setInterval('for(v="visibility",b=document.querySelectorAll("blink"),a=b.length;a--;)c=b[a].style,c[v]=c[v]?"":"hidden"',999)