Twitter is announcing a straightforward way for advertisers to join in the conversation around major events. Not that the service has lacked ads around, say, the Super Bowl. But Ameet Ranadive, the company’s senior director of revenue products, said that until now, buying those ads has been a “very manual” process, with advertisers piecing together the right keywords, Twitter handles and geographies to target. On the other hand, with Twitter’s new event targeting, anyone with a Twitter Ads account can browse a calendar of upcoming events, look at data around the size and demographics of the Twitter audience around each event — then, if they like what they see, they can target an ad campaign at that audience. Ranadive said Twitter looks at “a variety of user engagement signals” to identify that audience — it’s not just people who are tweeting, but also those who are looking for and engaging with content around the event. And event coverage will expand over time. (Twitter says it...