In the 2020 race for the White House, small donors are expected to play a more significant role than ever before. With so many Democratic candidates running, and only so much money to go around, whom small donors choose to support will determine in part which contenders will have the cash to compete — and who will not.

So, what clicks with donors online?

The Times analyzed six years of online donations to potential 2020 candidates through ActBlue, the Democratic Party’s main donation-processing platform, to tally the number of donations each candidate has received by day.

[See the rankings of 2020 Democratic hopefuls with small donors.]

The findings show that the art of inspiring online donors is very much about timing: It’s about having a moment in the national spotlight — and then capitalizing on it. Also, small donors are just like the rest of us: procrastinators inspired by a looming deadline.

With that, here are six days when some current and potential Democratic candidates for president scored big online, and why:

Elizabeth Warren: “Nevertheless, she persisted”

The Senate majority leader, Mitch McConnell, just wanted Senator Elizabeth Warren to stop talking. Instead, Mr. McConnell, a Kentucky Republican, handed Ms. Warren, a Massachusetts Democrat, a sound bite that she leveraged into her single biggest day of online donations.