Typography (from the Greek words τύπος(typos) = form and γραφή(graphy) = writing) is the art and technique of arranging type. The arrangement of type involves the selection of typefaces, point size, line length, leading (line spacing), adjusting the spaces between groups of letters (tracking) and adjusting the space between pairs of letters (kerning). Type design is a closely related craft, which some consider distinct and others a part of typography; most typographers do not design typefaces, and some type designers do not consider themselves typographers. Typography is performed by typesetters, compositors, typographers, graphic designers, art directors, comic book artists, graffiti artists, clerical workers, and anyone else who arranges type for a product. Until the Digital Age, typography was a specialized occupation. Digitization opened up typography to new generations of visual designers and lay users. According to David Jury, "Typography is now something everybody does."
Google now has something called Google Web Fonts It's a project to ensure webmasters, designers and developers have free and easy access to a choice of rich, free, quality typography for their websites.
Via: Fast Company