Starting this week, you'll also be able to "specify topics to contextually target your ads to pages in the Google Display Network. With this additional contextual targeting option, you'll be able to select from over 1,750 topics and sub-topics to target your ads, helping you quickly reach a broad audience across the web that's actively engaged with content related to your business," revealed Google.
Using topics versus keywords to target your ads: "Using topics to contextually target your ads offers broad targeting and reach, and is a good way to connect with large audience quickly and easily to generate awareness or drive sales. When using topic targeting our system looks at all the terms on a page to determine the topic of the page, and is less reliant on particular keywords. While using keywords to contextually target allows you to target ads to more specific set of pages in Display Network, since you use individual keywords. However, both targeting options can be used together to effectively reach an audience across the GDN," explains Google.
You can also exclude topics and sub-topics to refine your targeting.
As with other targeting options on GDN, contextual targeting by topic supports all ad formats, such as text, display, video and rich media as well as all bidding options, such as cost-per-click (CPC), cost-per-thousand impression (CPM), and cost-per-acquisition (CPA). In addition, you still have access to URL-level reporting and other tools such as Conversion Optimizer.