The search giant’s “Google Alerts” feature, which automatically notifies you when a subject appears online in news outlets, blogs or elsewhere, is now adding video to its arsenal, the company announced on its official blog. Users can choose to receive an e-mail when certain terms show up in a new video’s text description.

As Google and others make it easier to find online video, it is likely to make publishers feel more confident that they will be able to make money off of their content if they put it on the Web. Such moves by search engines and online ad networks helped spur the blogging revolution several years ago.

Google’s latest move also underscores the growing importance of online video, and Google’s determination to play a major role in how the medium matures.

Since Google bought YouTube, the top video destination on the Web, for $1.65 billion in stock last October, the company has continued its efforts to work video into its advertising business. The company this year introduced a pilot program, InVideo, for embedding ads in online programming. Google is also developing its Google Video site into a video search engine, while also sharing that technology with its main search site.

Rivals Yahoo (YHOO) and Microsoft (MSFT), meanwhile, are not standing still. Yahoo in particular has directed its business units to launch new efforts for weaving video into what they present to users, in hopes of capturing ad dollars that are migrating toward online programming.