流量平台的“Upstream Sites”

dwind

今天用alexa搜了几个流量平台，发现一个现象，这些流量平台连接的是那么的紧密，小白不太明白，希望有明白人来指点迷津：

在“Upstream Sites”项TOP里，各流量平台都出现了其他流量平台的影子，why？



buzzcity.com：
Upstream Sites

Which sites did people visit immediately before this site?

[td]

Site	Percent of Unique Visits
1.  google.com	11.9%
2.  facebook.com	3.7%
3.  google.co.in	2.4%
4.  plugrush.com	2.1%
5.  airpush.com	1.9%

popads.net：
Upstream Sites

Which sites did people visit immediately before this site?

[td]

Site	Percent of Unique Visits
1.  onclickads.net	2.9%
2.  openload.co	2.5%
3.  popcash.net	1.3%
4.  youtube.com	1.1%
5.  shink.in	1.1%

plugrush.com：
Upstream Sites

Which sites did people visit immediately before this site?

[td]

Site	Percent of Unique Visits
1.  google.com	9.2%
2.  exoclick.com	3.5%
3.  popads.net	2.7%
4.  facebook.com	2.7%
5.  youtube.com	2.3%