Lori Senecal, chairman-CEO of advertising agency Kirschenbaum Bond Senecal + Partners, grew her Twitter followers the old-fashioned way for nearly four years, earning 1,500 devotees tweet by tweet, as she wrote in a recent post on Ad Age. But on a recent Friday night, she shelved her slow-and-steady strategy and laid out $217 to put Twitter’s Promoted Accounts to the test. 

During her test, Senecal said she added 217 followers to her personal Twitter account in one weekend. Her page garnered 45,000 total impressions, and she said she was pleased with the quality of users who followed her.

But what about the long game? She said the followers she picked up are still engaged and following her profile.

For a business, though, Senecal told Inc. the best way to measure the ROI of Promoted Accounts depends on how the company follows up, not on whom the new followers are or how much they interact with you.

“You have to have the time to cultivate those relationships going forward,” she said. “It’s one thing to garner an audience, but if you don’t continue to engage that audience and return the value equation by giving them some reciprocal value, then you won’t be able to hold on to that audience, so the return on investment wouldn’t be strong eough.”

Promoted material, introduced in 2010, allow users to promote an individual account, tweet, or trend for a price—then Twitter catapults the item to the top of popular feeds or trend lists.