矢追 is a genre of 日本动漫 focusing on highly idealized male x male relationships. It's usually written 由 women for women, as opposed to bara created 由 and for gay men. (The men in bara are much more... manly. ^^) Yuri features girl x girl relationships and can be targeted at either men 或者 women.
Be careful with the terms- 矢追 technically boyxboy sex and yuri is girlxgirl sex. The right terms for romance would be shounen-ai and shoujo-ai respectively. Often, however, 矢追 and yuri are used as catch-all terms... which has been known to cause me some confusion. XD
(The picture is NaruSasu... a VERY 流行的 矢追 couple. :3)