Conditional redirections are classified differently than the iframe/javascript ones, because they are generally done though the HTTP headers (via .htaccess) to redirect users from certain browsers or locations to malware/malicious locations.
Referrer or user agent redirections. Happens when a user coming from a search engine (like Google) or certain user agent (Googlebot or MSIE) gets redirected to a malicious domain.
Anyone coming from a search engine, gets redirected to a russian site::