For Amazon, there are several big blocks of off-site drainage

1. Social media traffic (Facebook, Twitter, Reddit, etc.)

2. Video and photo sharing sites (YouTube, Instagram, Pinterest, Flickr, etc.)

3. Professional deal BBS, discount, (in the United States have Slickdeals Kinja, Dealnews, Dealwiki, Techbargain, Bensbargains, Britain has HotUKdeals, etc.).

4. Review websites, blogs, etc. (CNET, TechRadar, The Verge, TechCrunch, Digital Trend, etc., in no particular order).

5. The company's official website, the independent station (generally speaking, the independent station drainage mainly facilitates the in-station transaction, but there are also Amazon shopping entrances based on the habits of some buyers).

6. Google ads and Facebook ads (this is the big hole, because Google ads are mostly for independent sites, and so are Facebook ads, for reasons I'll go into below).