If you're a fan of "spy" movies and novels, or enjoy spending your time reading and watching such material, you may know about the concept of "intelligence" networks. These are groups of people who devote their time, clandestinely gathering and sending information, from one country to another.
Intelligence networks are large, and contain confusing and redundant casts of characters. These large numbers are necessary, to prevent the host country from detecting and stopping the activities of the networks. Besides the "spies" ("intelligence"), there is an equal but opposite activity - "counter intelligence". The goal of the "counter intelligence" personnel is to detect the intelligence activities of an enemy country, and to destroy (or hijack / mislead) such activity when it's detected.
When intelligence activity, conducted by an enemy country, is detected in a host country, the host country then starts from the detected activity and tries to detect and round up the entire intelligence network. This is a basic vulnerability of any intelligence network - detection of one component of the network can lead to detection of the entire network.
In Blogger blogs, one will find networks of "affiliate marketing" blogs, possibly involving GPT / PTC / PTS / PTW activity. When one blog is classified by the Blogger spam interdiction process, fuzzy analysis of the "affiliate" links will frequently lead to identification of multiple blogs, involved in the same activity.
As in "intelligence network" detection, "affiliate marketing" network detection starts with the classification of one blog, and analysis of links from and to that blog. Detection of "reciprocal" links between two blogs makes it likely that both blogs are involved in the same activity. If one blog is classified as a spam host, this then leads to the classification of both blogs, and more blogs which they jointly link from and to, as spam hosts.
In other words, an entire "affiliate marketing" / GPT / PTC / PTS / PTW network can be brought down, starting with classification of one blog.
If your blog is part of an "affiliate marketing" network of fraudulent activity, with reciprocal links between the blogs, shuffling your readers from blog to blog, that may be why your blog is now classified as spam - and that is why you are now here.