According to Netcraft’s most recent web server survey, the amount of hostnames on the Internet has doubled within the past three years. At the end of March, Netcraft said it identified a total of 80,655,992 websites, which represents an increase of 3.1 million since the end of February. In March of 2003, Netcraft reported the existence of about 40 million web sites.    Apache, the most popular web server software on the Internet suffered a substantial slide in market share in March, the research firm said. Compared to the previous month, Apache lost six percentage points from 68.7% to 62.7% due to a large-scale migration from Apache to Microsoft software at domain registrar GoDaddy. Microsoft gained almost five percentage points and stands now at 25.2%. According to Netcraft, GoDaddy will shift a total of 4.4 million hostnames from Apache to Windows Server 2003.