A year and a half ago I left my role as as SEM manager to focus solely on SEO. Now I'm moving back into a role incorporating both SEO and PPC for an online retailer and I feel a little behind in terms of PPC developments.
Can someone recommend some big developments in this time that I should be reading up on, especially with regards to online retail? I think the last big change I worked with was BMM in AdWords! I know I need to get up to speed on retargeting/remarketing for a start.