The Drum’s special report on Performance Marketing is published on 17 February.

Affiliate/publisher/partner: Drives traffic to online advertisers/merchants, usually via content on a website or blog, or paid traffic. The affiliate earns commission from the merchant when an agreed action (e.g. sale or lead) occurs.

Affiliate network: A network enables affiliates/publishers to easily access a wide range of affiliate programmes, and vice versa. Networks generate revenue by charging the merchant a percentage of the commission paid to affiliates.

Affiliate programme: The performance-based form of marketing to promote a merchant's products or services. The programme may include a small or large number of affiliates depending on the merchant's needs. The merchant pays a commission or lead rate on sales, enquiries or other agreed action to the affiliates in the programme.

Affiliate Management Agency: An independent company utilised by some merchants/advertisers to strategically manage their affiliate programmes; recruiting the ideal blend of affiliate partners.

Banner: Graphic ad displayed on a website.

Cashback site: A type of affiliate website which pays its members a percentage of money earned when they make a purchase via an affiliate link on the site.

CTR: Click through rate is calculated by dividing the number of clicks an ad receives by the number of impressions. For example, if a banner advert was displayed 100 times and received 20 clicks, the CTR would be 20%.

Conversion: The percentage of people who purchase after clicking on an affiliate link.

Cost per Lead: A commission structure which involves the merchant paying the affiliate an agreed fee for each potential customer referred to the merchant's website.

Cost per Sale: A commission structure which involves the merchant paying an affiliate a percentage or flat fee for a sale of a product or service to a customer referred to the merchant's site.

CPA: Cost per acquisition is what a merchant is willing to pay for an acquisition/lead.

CPC: Cost per click is one of the payment models by which an advertiser pays for each click through made on their ad.

CPM: Cost per thousand is one of the online payment models by which an advertiser pays for every 1000 impressions of their ad.

Merchant/advertiser: Online retailer or business owner.

PPC: The practice of paying for traffic from search engine advertising services on a cost per click basis.

Reach: The number of unique visitors that visited a site over a certain period, expressed as a % of the universe for the demographic category.

Voucher code: A voucher code is supplied by a merchant to an affiliate for them to promote on their site and give money off a purchase.