zilonjakir

This is wordpress visitors counter plugins. when install this plugins autometically create a table, name wp-counter_total and created a widget. this widgets show three options. 
1. current visitors 
2. todays visitors 
3. total visitors
and when any visitor, any place who browse your website then automaetically change your visitors number without page refresh.

WordPress Visitors

It's a simple plugin to count your website's current visitor, todays hits, total hits without page refresh.

Silkalns

WP Chill

Cristian Raiber

A very useful plugin for everyone using WordPress. Adds reCaptcha security to the WordPress login form, register form and comment form. This plugin could help your blog get rid of a lot of spam comments or brute-force attacks.
Nothing gets passed it if the reCaptcha doesn’t validate.
A few notes about the plugin:
<ul>
<li>Supports audio or image captcha types</li>
<li>Can generate the reCaptcha image / audio type in a number of predefined languages</li>
<li>Adds reCaptcha protection to the WordPress login form</li>
<li>Adds reCaptcha protection to the WordPress register form</li>
<li>Adds reCaptcha protection to the WordPress comment form</li>
<li>Adds reCaptcha protection to the WordPress recover password form</li>
</ul>

Uber reCaptcha

This plugin adds the reCaptcha form to the WordPress login form, recover password form, register form and comment form.

WordPress Visitors vs Uber reCaptcha