1. A computer-implemented method comprising: receiving an advertisement, the advertisement including text to be displayed in a user's mobile browser, wherein the mobile browser displays the ad along with other non-ad content, and wherein the text of the advertisement includes one or more Latin and one or more non-Latin characters; determining whether at least some of the text includes characters that should be displayed in a layout direction that is vertical in the mobile browser, wherein the determination is based at least in part on a determination that one or more non-Latin characters are in the text, and determining that none of the text should be displayed in the layout direction that is vertical if the text includes a number of Latin characters that exceeds a first defined value, the text includes a number of consecutive Latin characters that exceeds a second defined value, or if a ratio of Latin characters to all characters in the text exceeds a third defined value; determining whether the mobile browser supports floating text columns in response to a determination that at least some of the text includes characters that should be displayed in the layout direction that is vertical; and in response to a determination that at least some of the text includes characters that should be displayed in the layout direction that is vertical and that the mobile browser supports floating text, displaying the one or more non-Latin characters of the advertisement in the layout direction that is vertical in a floating text column that is distinct from a display of the other non-ad content in the mobile browser and wherein the one or more Latin characters of the advertisement are shown horizontally.