For some sites, semalt related traffic can sap performance bandwidth.  Here’s the most recent .htaccess directives blocking semalt traffic to your sites:

# Block SEMalt botnet
SetEnvIfNoCase Referer fbdownloader.com spammer=yes
SetEnvIfNoCase Referer descargar-musicas-gratis.com spammer=yes
SetEnvIfNoCase Referer baixar-musicas-gratis.com spammer=yes
SetEnvIfNoCase Referer savetubevideo.com spammer=yes
SetEnvIfNoCase Referer srecorder.com spammer=yes
SetEnvIfNoCase Referer kambasoft.com spammer=yes
SetEnvIfNoCase Referer semalt.com spammer=yes

Order allow,deny
Allow from all
Deny from env=spammer