Google often penalized website .Many popular site suffered and band by google. Why Google do this.
Google has several Quality Guidelines. Violating them could lead to penalties or outright blacklistings. You can usually tell if a site has been blacklisted if it is unavailable in Google search when you search for the domain name.
The top reasons sites get blacklisted include:
These types of activities usually lead to manual reviews by the spam team and will often lead to blacklistings.
Other activities can lead to ranking & traffic penalties that Google won't call penalties, but essentially are. These include:
These penalties are usually algorithmic, but can be long lasting. Many sites fall into these traps unknowingly or as an attempt to take short cuts.
I've seen even the smartest developers try to hide content in various ways because they want search traffic, but don't want to show the content to visitors.
Penalties can kill websites/companies. Algorithms change constantly and many high quality, clean sites get caught in algorithm false positives, unknowingly being categorized as search spammers in Google's long, massive battle to squash search spam.
For example, in August 2018 a new core algorithm was released by Google that hurt many quality sites (and low quality sites). In 2019 they retracted some of the changes, but the algorithm is far from perfect.
Some reasons Google often uses to penalize websites: