Because of this, most webmasters will create the titles on a website as images. This also holds true when you send a document by email. If the font you have used is not installed on the recipients computer, they are not going to see it the way you intended. I discovered this when I sent my bills out with my letterhead created in text. Your computer will attempt to find a similar font to display but it just ain't the same.
Serifs improve readability by leading the eye along the line of type.
So a Sans Serif T does not have the small cross lines and flourishes. Generally a low-contrast design. Sans serif faces lend a clean, simple appearance to documents. Your browser has settings for default fonts and default text colour so if your webmaster has not coded in the type of font and the colour, the default font and colour will show. On most browsers this is set at Times New Roman and black.