Get Current URL in Magento and show something

You can retrieve the current URL path by doing the following:

$currentUrl = Mage::helper('core/url')->getCurrentUrl();
$url = Mage::getSingleton('core/url')->parseUrl($currentUrl);
$path = $url->getPath();

Then using some basic logic, you can target the /blog page.

$blogPaths = array('/blog', '/blog/', '/index.php/blog/');
if(in_array($path, $blogPaths))
{
    //Do some