Sen. Kamala Harris of California is leading the field of Democratic presidential candidates in capturing the public's attention during the opening wave of the 2020 campaign.

Why it matters: That puts Harris in a strong position to help set the Democratic primary agenda, much as Rep. Alexandria Ocasio-Cortez is doing for the House Democratic agenda.

The numbers from the past three months (Nov. 12–Feb. 12) say it all:

On Google, Harris was searched twice as often as Sens. Elizabeth Warren and Bernie Sanders, who were next closest, according to Google Trends.

Instagram interactions, according to CrowdTangle:

Harris: 8.3 million Sanders: 4.6 million Warren: 2 million

Twitter interactions, according to CrowdTangle (combining Senate and personal accounts):

Harris: 14.4 million Sanders: 8 million Warren: 4.1 million

The exception is Facebook, where Sanders gets much of his clout, according to CrowdTangle (combining Senate and personal accounts):

Sanders: 22.1 million Harris: 2.4 million Warren: 2.3 million

In the past three months, articles about Harris have generated 16.5 million interactions on Facebook and from shares on influential Twitter accounts, according to social media analytics company NewsWhip.

That compares with 14.2 million for Warren and 10.6 million for Sanders.

Harris' follower growth across those platforms during the past three months has been striking:

On Facebook , her main account has added 123,000 fans, per CrowdTangle. The next closest jump among 2020 competitors is Beto O'Rourke with 51,000.

, her main account has added 123,000 fans, per CrowdTangle. The next closest jump among 2020 competitors is Beto O'Rourke with 51,000. On Instagram, Harris has added 613,000 followers. The next closest spikes came from O'Rourke and Warren with 200,000 followers added.

Harris has added 613,000 followers. The next closest spikes came from O'Rourke and Warren with 200,000 followers added. On Twitter, she has added 420,000 followers. Next closest is O'Rourke with 245,000.

The big picture: The size of the major social media platforms makes for a useful barometer of public opinion and interest. They also signal a level of enthusiasm that is difficult to capture with traditional polling.

Yes, but: Early polling indicates former Vice President Joe Biden and Sanders have the highest favorables among 2020 Democrats. But, this early in the cycle, those numbers are often just a sign of name recognition.

Having already announced — or formed exploratory committees — Harris, Warren, and Sens. Kirsten Gillibrand, Cory Booker and Amy Klobuchar have benefited from announcement-driven spikes of interest. The others can expect that when it's their time — but Harris has dominated the attention well beyond her initial announcement.

The bottom line: President Trump showed in the 2016 campaign that the ability to generate attention and make the public care about you is a precious commodity. Maintaining that edge, more than fundraising totals or a ground game, could be the key for Harris in 2020.

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