In my blog's dashboard I can choose to customize my fonts by going to Appearance->Custom Design -> Fonts. I can then change fonts and preview how they would look on my blog (I haven't paid for the blog customization feature yet).
Many of the fonts look great - Liberation Sans, Droid Sans, Proxima Nova, etc. However, I see that none of these fonts are installed by default on Windows 7. For reference see: http://www.microsoft.com/typography/fonts/product.aspx?pid=161 for Windows 7 and http://www.microsoft.com/typography/fonts/product.aspx?PID=148 for Office 2007.
My question is how will my blog's visitors be able to see the custom fonts I choose if these fonts are not already installed on their computers? I don't want to choose these customized fonts only for my visitors to see generic 'serif' or 'sans serif' when they view my blog.