Over the last eight years I have had dozens of websites in several different industries. Most of the websites I have built have been WordPress. Within the WordPress dashboard, comments are allowed by default. If you want to turn comments off you have to manually do it. For this reason, I have allowed comments to remain on for a number of my websites. That said, comments are not good for every blog or business website and here is why.
If you are not going to monitor and review each comment you will likely want to turn them off. If your website is getting more than 10 visitors a day you are going to find that spam comments coming in on an hourly basis. Some of my more highly trafficked websites receive 100’s of spam comments each and every day. If I didn’t go through and manually review all the comments they would fill my websites up with garbage. This could possibly get me penalized by the Google algorithms.
If you do not have the time to manually review each and every comment I would strongly suggest turning them off. You will get so many spam comments that it will affect how Google sees your website. Remember that Google crawls all the content on your website so if there are spam comments for certain types of prescription drugs or get rich quick schemes Google will see you as someone promoting that type of product.
If you do have time to manually review every comment I would suggest keeping comments turned on. One of the reasons my website gets over 3000 search visitors every single day is because of the lengthy content created through comments. There are a handful of 300 word articles I have published that have ended up being well over 10,000 words because of the discussion in the comments. I closely monitor this discussion and make certain it does not go sideways.
Comments are a very tricky aspect of SEO and ranking in Google search. While quality comments can help your website rank for long tail keywords, spam comments can hurt your website and the user experience. The best thing you can do is to think about the user experience. If you want to rank on the front page of Google search you will need to create a great user experience.
Take some time to see what your visitors are doing on your website. Do they want to comment? Are they trying to contact you? Would they like to vote on a poll? Would YouTube videos make their experience better? Do everything in your power to make your visitor stay on your website and consume all of the content you have produced.