Anyone who sends shoppers to a brand through an affiliate programme for commission: content sites, voucher sites, creators, extensions.
Networks call the brand the advertiser and everyone who promotes it a publisher. Brands often say affiliates or partners. A publisher joins the network, applies to the brand's programme, and once approved gets tracking links that carry its own publisher id. They come in many kinds:
- Content sites, with reviews, guides and comparisons.
- Voucher sites and cashback sites, which list codes or pay members part of the commission.
- Coupon extensions, which offer codes at checkout.
- Creators and newsletters, with codes and links of their own.
- PPC affiliates, which buy search traffic.
- Sub-networks, which join as one publisher with many behind them.
Google Ads calls anyone who buys ads an advertiser, affiliates included. So the advertiser Google names on an ad on your brand's search can be a publisher on your programme, and the name in your network's report can be a different company from the one on the ad.
In the UK, the ASA says the advertising rules apply to affiliate marketing, and that the brand and the affiliate are both responsible for an affiliate's ads being clear that they're ads.
Google's own help and policy pages first.