Changing commenting platforms...will deleting old comments hurt SEO?

[TMI.com]

Hi everyone,

We've decided to move away from Disqus and use Facebook comments on one of our blogs. Our users prefer it, and we saw traffic increase when we did it on another site. My question is, will removing old comments (we have hundreds of them per post) hurt my seo? I've scoured the internet for an answer but can't find anything up to date. Old best practices said to keep old comments. What do you think?

Thanks!

[max.favilli]

Is you current commenting system allowing FB logins?

Because in my experience what users like about FB commenting is just the ability of commenting without first need to signup.

I would stick with your current commenting system and just allow social logins, if you don't have already.

[Mobilio]

TL;DR - It dependents.

Main answer is - how you get traffic? If this is traditional way - "write great content and they will follow" this also bring comments. And comments create new content with new traffic. Because Google/Bing/Yahoo can index content and comments too. Moz uses this way in their blog section for example. This is organic way.

But in new way - comments in social networks bring traffic. Because more people seeing that person comment/share/like something and they do "curiosity driven research" what is this content. But this bring only social network traffic since not all of Facebook comments can be indexed from search machines. This is social way.

This is theory about traffic and i describe only two of them (they're much many but i simplify little bit things). Now turning things into practical. Disqus can have some issues with crawling comments from Google. This is well known and described many times: https://help.disqus.com/customer/portal/articles/762307-why-isn-t-google-indexing-my-comments-
Facebook comments can't be indexed at all too from Google. There are some articles from 2011 that they can but i can't find working example.

That's why it's best if you can check - are your existing comments indexed? If they are you can leave both commenting systems. It's much better. If they wasn't indexed you can switch to Facebook commenting system. Also check on other site can you find some Facebook comment in Google.

And one suggestion "Don't Build Your House on Rented Land". If you can use your own commenting system this will be much better. Just like Moz.