Stands for "Cost Per Lead."
CPL is a term used in online marketing that refers to how much an advertiser pays a website or ad network each time they acquire a lead through an advertising campaign. This advertising model is also called "online lead generation." Once the ad campaign gathers leads, further marketing efforts attempt to convert those leads into customers.
Advertisers running a campaign using a CPL pricing model tend to have a different focus than those using a CPC (Cost per Click) or CPM (Cost per Mille) model. Instead of paying for people to click or view an ad, a CPL model pays for leads — someone who has chosen to sign up to receive more information or express interest. First, an online ad sends a potential lead to the ad campaign's landing page. From there, they explicitly choose to share their information and express interest by the method set by the ad campaign — they may sign up for an email newsletter, a rewards program, a free trial, or otherwise share their personal information and express interest.
These advertising campaigns tend to cost more, but the advertiser ends up with a more-valuable pool of leads. Leads who choose to sign up are more likely to become paying customers and even repeat customers.