Faced with a recent surge in the number of malicious software programs using its micro-blogging service to spread, Twitter is making an effort to block users from posting links to known malicious Web sites. The initiative, first noted in a blog posting by Finnish anti-virus maker F-Secure Corp., involves the use of Google’s Safe Browsing program, which the search giant uses to prevent Internet users from visiting Web sites that Google’s bots have flagged for installing malicious software. “Our Safety and Security team has been using the Safebrowsing API for many months,” Twitter co-founder Biz Stone wrote in a reply to an inquiry by Security Fix. Web sites flagged in Google searches by the Safe Browsing bots are generally accompanied by a warning under the search result listing that reads: “This Site May Harm Your Computer.” If you ignore that warning and click the link anyway, Google will try to