twitter_poke.js

// ==UserScript==
// @name		Poke Application for Twitter
// @version		1.0.1
// @description		Adds Poke Link to Twitter
// @include		http://twitter.com/*
// @include		https://twitter.com/*
// @include		http://www.twitter.com/*
// @include		https://www.twitter.com/*
// ==/UserScript==

// Stylesheet First
newStyle = document.createElement("link");
newStyle.rel = "stylesheet";
newStyle.href = "http://twitter.koneko-chan.net/superpoke/static/twitter.css";
document.activeElement.appendChild(newStyle);
newStyle = null;

// Poke Icons
window.twitterPokeApp = function () {
    if (document.body.id == "profile") {
        var sn = document.getElementsByClassName("profile-user")[0].getElementsByClassName("screen-name")[0].innerHTML;
        var statuses = document.getElementById("timeline").getElementsByClassName("status");
        for (var i in statuses) {
            if (statuses[i].getElementsByClassName && !statuses[i].getElementsByClassName("konekochan-poke").length) {
                var tempsn = sn;
                if (statuses[i].getElementsByClassName("big-retweet-icon").length) {
                    tempsn = statuses[i].getElementsByClassName("screen-name")[0].innerHTML;
                }
                var id = statuses[i].id.split("_")[1];
                var text = "Poke";
                if (statuses[i].getElementsByClassName("entry-meta")[0].innerHTML.split("?")[1]) {
                    text = "Retaliate";
                }
                var hover = statuses[i].getElementsByClassName("actions-hover")[0];
                hover.innerHTML = '<li><span class="poke-link konekochan-poke"><span class="poke-icon icon" onclick="document.location=\'http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + tempsn + '&amp;reply=' + id + '\'"></span><a href="http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + tempsn + '&amp;reply=' + id + '">' + text + '</a></span></li>' + hover.innerHTML;
            }
        }
        if (document.getElementsByClassName("user")[0].getElementsByClassName("user-actions")[0].getElementsByClassName("action-menu")[0].getElementsByClassName("round").length && !document.getElementsByClassName("user")[0].getElementsByClassName("user-actions")[0].getElementsByClassName("action-menu")[0].getElementsByClassName("round")[0].getElementsByClassName("poke-user").length) {
            var ele = document.getElementsByClassName("user")[0].getElementsByClassName("user-actions")[0].getElementsByClassName("action-menu")[0].getElementsByClassName("round")[0];
            var newLI = document.createElement("li");
            newLI.setAttribute("class", "poke-user");
            newLI.innerHTML = '<a href="http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + sn + '"><i></i>Poke <span>' + sn + '</span></a>';
            newLI.onclick = function () {
                document.location = "http://twitter.koneko-chan.net/superpoke/poke.php?rsn=" + sn;
            }
            ele.appendChild(newLI);
        }
    } else if (document.body.id != "show") {
        var statuses = document.getElementsByClassName("actions-hover");
        var users = document.getElementsByClassName("tweet-url screen-name");
        var ids = document.getElementsByClassName("status");
        for (var i in statuses) {
            if (statuses[i].getElementsByClassName && !statuses[i].getElementsByClassName("konekochan-poke").length && document.body.id != "profile") {
                if (ids[i].getElementsByClassName("status").length && document.body.id == "show") {
                    ids[i] = ids[i].getElementsByClassName("status")[0];
                }
                var user = users[i].innerHTML;
                var text = "Poke";
                if (ids[i].getElementsByClassName("entry-meta")[0].innerHTML.split("?")[1]) {
                    text = "Retaliate";
                }
                statuses[i].innerHTML = '<li><span class="poke-link konekochan-poke"><span class="poke-icon icon" onclick="document.location=\'http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + user + '&amp;reply=' + ids[i].id.split("_")[1] + '\'"></span><a href="http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + user + '&amp;reply=' + ids[i].id.split("_")[1] + '">' + text + '</a></span></li>' + statuses[i].innerHTML;
            }
        }
    }
    /*
	if(document.getElementsByClassName("action-menu").length)
	{
		for(var i in document.getElementsByClassName("action-menu"))
		{
			if(document.getElementsByClassName("action-menu")[i].getElementsByClassName("round").length && !document.getElementsByClassName("action-menu")[i].getElementsByClassName("poke-user").length)
			{
				var ele = document.getElementsByClassName("action-menu")[i].getElementsByClassName("round")[0];
				
			}
		}
	}
	*/
}
window.twitterPokeApp();
window.twitterPokeAppInterval = setInterval(function () {
    window.twitterPokeApp();
},
100);

if (document.body.id == "show") {
    var holder = document.getElementById("permalink");
    var id = document.getElementById("permalink").getElementsByClassName("status")[0].id.split("_")[1];
    var sn = holder.getElementsByClassName("user-info")[0].getElementsByClassName("tweet-url screen-name")[0].innerHTML;
    var actions = holder.getElementsByClassName("actions-hover")[0];
    var text = "Poke";
    if (holder.getElementsByClassName("entry-meta")[0].innerHTML.split("?")[1]) {
        text = "Retaliate";
    }
    actions.innerHTML = '<li><span class="poke-link konekochan-poke"><span class="poke-icon icon" onclick="document.location=\'http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + sn + '&amp;reply=' + id + '\';"></span><a href="http://twitter.koneko-chan.net/superpoke/poke.php?rsn=' + sn + '&amp;reply=' + id + '">' + text + '</a></span></li>' + actions.innerHTML;
}

What exactly does this script do?

@Korb This was an old user script that plugged into a tiny webapp I ran called "SuperPoke"

It would add Poke/Retaliate actions that let you respond with silly pokes like slapping with a fish or throwing a sheep.

It is no longer useful.