Google announced that advertisers engaged in keyword-based contextual targeting on the its Display Network will now also be able to do so in a new way - selecting from over 1,750 topics and sub-topics.

Using keywords for contextual targeting has allowed advertisers to focus on a very specific set of pages including those terms in the display network Using topic-based contextual targeting however will be quite a departure.

Google will analyze all of the terms on a page to determine the topic - a pretty significant shift for those involved with contextual targeting through Adwords and publishers profiting from the ability via Adsense.

As with other targeting options on the Google Display Network, contextual targeting by topic supports all ad formats, such as text, display, video, and rich media, as well as all the available bidding options, such as cost-per-click (CPC), cost-per-thousand-impression (CPM), and cost-per-acquisition (CPA).

All in all, expect more advertisers to start exploring the opportunities in the Google Display network as its has quickly, thanks to topic targeting, become more accessible and “friendly” to those that may shy away from the complexities of keyword-based targeting.