Stop Spam Registrations in Joomla
Tired of spam registrations in your Joomla website? Joomla 2.5 version now has built in plugin to add recaptcha. Recaptcha is free service from Google which provides a user to enter the two words (These words can't be read by bots) before registering.
Step 1: Go to http://www.google.com/recaptcha. You need a Google Account to log in. Get a public key and private key for your website.
Step 2: Go to Plugin Manager in your Joomla backend and open the Captcha Recaptcha (You can filter by type) plugin. Enter both the keys generated in step 1 in parameters. Don't forget to enable the plugin and save.
Step 3: Check your registration page. You should see recaptcha by now. Try a dummy registration to see yourself how it works.