Nielsen announced today that it’s acquiring ad tech company Vizu. This isn’t the kind of deal where you have to wait months for something to happen. Executive Vice President for Ad Effectiveness Scott McKinley says it’s a “plug and play acquisition,” and in fact, Vizu’s Ad Catalyst will be available immediately as part of Nielsen’s online ad measurement tools.

Until now, Nielsen measured an online advertising’s reach but not its effectiveness (something that it does measure on television). When the company decided to change that situation, McKinley says Vizu was the obvious choice, since it’s the leader in the field. Vizu’s technology shows brief polls to people who have seen an ad, and otherw ho haven’t — so advertisers can use the polls to determine whether campaigns seem to improve people’s perception of their company. McKinley says one of Vizu’s big draws is the fact that it provides advertisers with real-time data, so that they can tweak campaigns based on the results.

Eventually, Nielsen will do more to integrate Vizu’s features with its measurement of online ad reach, and with its cross-platform products. The goal, McKinley says, is “bringing data out of Vizu systems and connecting up with how we measure television, so we can offer advertisers a complete picture of reach and effectiveness across television and online.”

Vizu raised more than $10 million in funding from investors including Ron Conway, Esther Dyson, Draper Fisher Jurvetson, iNovia Capital, and Greycroft Partners. The financial terms of the deal were not disclosed, but McKinley says the Vizu team will be joining Nielsen, and that it will continue working out of its San Francisco offices.