If Website is get penalized by any algorithms, how would we come to know it?
There are a lot of websites who indicate if your website got some problems. But you can do some research on Google
You can do that first (if you have Google Webmaster Tools) login to the account and you will see there if you are under penalties or not.
There are 2 types, one is Manual Penalty: A human (probably from the webspam team), imposed a penalty to your website. This can happen because of a number of reasons and it can be either site-wide i.e. affecting the website as a whole or partial i.e. affecting only some pages of your site.
When this is the case, Google will give you an indication of what the problem is together with a list of actions you can take to correct the issues. Once you make the necessary changes, you can submit a reconsideration request and they will tell you if the penalty has been removed or not.
The other is Algorithmic Penalty: This is the most common type and it is automatic. Algorithmic penalties are not reported to webmaster.
If you think a website’s visibility/SERP’s has been penalized from a Google update and there are no manual penalties in your Google Search Console, here is a method to check the validity of your hunch.
Want to look for your website visitors. Go to Acquisition > Source/Medium
The click “google / organic” which will let you segment this channel.
Change the report dates to include several months behind when you suspect the website was affected by a Google search update. * Note normally we include at least a whole previous year of data to rule out a false positive from seasonality.
Using the report’s graph look for a sharp downward trend which maintains itself over a few weeks or months. Depending on the time frame of the report you might want to change the graphs display to weeks or months.
If you find a consistent dip take note of a few weeks during and around the traffic loss.
If you find a match between a date of known Google algorithm update and the loss of traffic both the above websites offer additional information about the type of update. Also like to mention there are a few services, such as Fruition, that offer “Penalty Checkers” services that we have found helpful.