Twitter's new Moments tab. Source: Twitter

During Twitter's (TWTR) short 30-minute conference call announcing that Jack Dorsey is now the company's CEO, Project Lightning was mentioned no less than three times. Not once, however, did management let on that the new feature, now officially dubbed Moments, would start rolling out the next day.

But Project Lightning officially struck in the U.S. last week, and expectations are high that it will help change Twitter's fortunes. Dorsey spared nothing when he told investors on the company's second-quarter earnings call that previous product features designed to engage and retain new users have failed. He also touted how great Project Lightning was, and he believes it will reinvigorate user growth for Twitter. Can Moments live up to the lofty expectations?

What exactly is Moments?
Moments has three components.

First, clicking on the Moments tab inside Twitter directs users to the Today section. These are Moments that are going on now, and clicking on any one of them will dump the user into a full-screen media experience featuring videos, photos, and sometimes just text. It's a similar experience to Snapchat's Stories.

Second, if a Moment is still happening, a user can elect to follow the Moment, which will fill his existing timeline with content around that topic or event. After the Moment, tweets from those accounts will stop appearing.

Third, the Moments tab also features tabs for Sports, Entertainment, Fun, and News. These tabs house some older content that is less time sensitive like Getty Images' "Weird & Wonderful Photos" Moment.

It's also worth noting that Twitter isn't the only curator for Moments. Getty Images put together the aforementioned photo collection; Buzzfeed has contributed its own take on Moments; and The Washington Post is using the medium to keep Twitter users up to date on world events.

What can Moments do for Twitter?
There seem to be three goals for Moments.

First, Moments is a highly engaging feature, giving existing users one more thing to do on Twitter. The feature also highlights Twitter as a source for content. I've discovered things I otherwise may never have found out -- Will Smith is going on tour next summer! -- and followed along with the AL Wild Card Game because of Moments. Increasing existing user engagement should lead to higher average revenue per user.

Second, Moments is a tool to onboard new users. There's a steep learning curve for Twitter, and Moments completely removes it by handing new users interesting content to read and to follow while highlighting other users they might be interested in following. It automatically builds a timeline, so new users can understand how the core product works, and it automatically stops following accounts when they're no longer interesting -- another key part of getting the most out of Twitter.

Finally, Moments is designed to re-engage users who have abandoned Twitter. This is a daunting task for Twitter, and Moments alone won't solve it. That's why Twitter will be running an ad campaign highlighting Moments, which could help the billion-or-so users that abandoned the service come back and give Twitter another shot.

Investors have soured on Twitter stock as user growth has slowed to a crawl. The company added just 2 million net new users for its app last quarter. Moments has a lot of potential to better retain new users signing up and bring back old users in order to start growing active users again.

One last benefit
Moments also represents a significant advertising opportunity for Twitter. There are two ways Twitter can benefit from engagement with the new Moments tab and increase average ad prices.

First, Twitter can place ads in the stream exactly like Snapchat does with Stories. These ads would benefit from taking up the full screen, which makes them more valuable than standard promoted tweets.

Second, Twitter can take the Buzzfeed approach and help brands create Moments around a certain product, promotion, or event. In fact, Buzzfeed's first Moment was about McDonald's All Day Breakfast. There's no reason Twitter's team of curators coupled with its sales team couldn't do the exact same thing. Depending on how popular Moments becomes after the initial novelty wears off, these sponsored Moments could be worth a lot.

It's still early, but the first impressions of Moments are very good. While the feature gives investors a reason to be optimistic, it remains to be seen if it can actually translate into the user growth and engagement investors want to see.