Blacklisting is when search engines like Google do not index your website pages. This generally happens because of poor SEO practises.
Some of the various reasons for blacklisting are:
Keyword Spamming
This generally happens when data given in META keyword tag is not related to the content of the page. If in your META tag, you have given cricket and content on the page is about web programming than there is a chance to get blacklisted.
Keyword Crowding
This happens when TITLE tag is just a collection of keywords without any connection between them.
Keyword Repetition
If you repeat keywords most often in META keyword tag than there is a chance to get blacklisted.
Keyword Drowning
It has bad effects on SEO but rarely used for blacklisting. It is basically giving more keywords in META keyword tag. 10-15 keywords are enough for this tag, 20 is ok but if you use 30-40 than some search engine may take it as spamming and blacklist your
site.
Mirror Websites
Mirror websites are sites with identical content but different URL’s. This was once a method used to gain high rankings in the search engines, but since search engines are smarter now, this will only get you penalized or blacklisted.
Doorway (gateway) Pages
Doorway pages are pages with little real content for your visitors that are optimized to rank highly within the search engines. These pages are designed so that visitors will move deeper into the website where the real content lies. Navigation to the doorway pages are usually hidden from the visitors (but not the SE robots) on the homepage.
Invisible Text and Graphics
Using invisible text (text the same or a very similar color to the background) was once used to spam a homepage and some inside pages with non-stop keywords and keyphrases. Also links to doorway pages and hidden site maps can be done with invisible text (or invisible graphics). Some designers will create a graphic link with a 1 pixel by 1 pixel raster image and link this to a hidden inner page such as a hidden site map.
Submitting Pages Too Often
Submitting the same pages to the search engines within a 24 hour period can get you penalized and may delay your website from being listed in the rankings. Some search engines believe that pages submitted sooner than every 30 days is too much. The 30 day rule is a good rule to follow when submitting to multiple search engines.
Automated Submissions to the Major Search Engines
Using an automated service or software to submit your website to the search engines can be extremely counterproductive. Most of the major search engines and directories accept manual submissions but do not like to be spammed with the automated ones.
Cloaking
Cloaking is the practice of deceiving both the search engine and the visitor by serving up different pages for each. The visitor sees a nicely designed and formatted page and the search engine robot scans a page of highly optimized text. Any practice that is deceptive should be avoided and the downfall of cloaking is that, if caught, the website can be banned permanently.
Using a Cheap or Free Web Host
Using a cheap or free web host can hurt in the search engine rankings. If a robot cannot access your site often enough, your site will be dropped from the search engines. Hosting is cheap, so if you are serious about your website get your own domain name and host not one like geocities.com/yoursite.
Sharing an IP Address
Sharing an IP Address even from a legitimate web host can get your site in trouble. If you have cleaned up your website from all of the techniques mentioned above and your website still does not get relisted by the search engines in a couple of months, check with your host to see if you are sharing an IP address with other sites. If so, you may consider moving your website to a new host who will give you your own IP address or at least one that is not shared with another company who has had their IP address (an yours) banned by the search engines.
Tools to check Blacklisting
Google Search Console – https://search.google.com/search-console/about
When a search engine blacklists a website it will block your listing off their site and stop your site from coming aboard again. This can be done by blocking the domain name, the IP address or both. So it is better to not take above steps and avoid search engine blacklisting.