One of the problems for League of Legends games that don't have some form of voice communication, is that players can only communicate through chat. This isn't really possible all the time, especially when things get frantic, so they often resort to pings. However with only two options there, these can sometimes be confusing. To alleviate this problem, Riot has introduced smart pings.
These give four new options to players: Danger, Enemy Missing, On My Way and Assist Me which can be used to specify plenty of things. It allows gamers to know exactly where their team mate is coming from and the path they will take - making ganks easier - as well as discounting the need to do "miss," or "ss" calls in chat.
Some other changes in this patch 3.03, also tweaks Xin Zhao, who has had nerfs to his Audacious Charge and Crescent Sweep moves - the idea behind the changes being that now he can't permanently slow his opponents while popping off his ulti with abandon. With this he should require a little more skill to play correctly.
Other changes improve tweaks to Kayle and Nidalee, who have had their excess power and damage reduction reduced respectively.
For a full changelog check out Riot's rundown here.