Once I signed up for a dating site. Once I signed up for a dating site.

Someone cYou would think the purpose of such sites’ purpose is dating?. You would think the purpose of such sites is dating.

"You would think" is a common (colloquial/informal) expression in English.

That would be an obvious assumption, but a number of users used the site for other purposes (assuch as social network) –ing by publisheding posts orand commenteding. That would be an obvious assumption, but a number of users use the site for other purposes such as social networking by publishing posts and commenting.

So I became a commentatoer and then tried to write (posts)some posts myself. So I became a commenter and then tried to write some posts myself.

"Commentator" is most often used for, for example, people who comment on sports games on TV.

I lost my interest toin the site whenafter I [went through all phases]. I lost my interest in the site after I [went through all phases].

It's unclear what you mean here by "went through all phases".

When I decided to review my English, I signed up for a site like this one (it was called Lang-8; rest in peace, Lang-8). When I decided to review my English, I signed up for a site like this one (it was called Lang-8; rest in peace, Lang-8).

InAt first eyglance, it seemed uncomfortable to me, so I gave up. At first glance, it seemed uncomfortable to me, so I gave up.

"At first glance, it seemed..." (which I assume is what you meant) is generally not used for talking about your own feelings e.g. "uncomfortable". "At first glance" is for talking about things you believe/guess to be true about something based on appearances. But when it comes to your own feelings about the website, there is no estimating/guessing, because you know exactly how you felt, namely uncomfortable. In this situation, I might use a phrase like "during my first time / first few times using the site" or "as an early user".

In a few months I returned and tried again and I find outound that I liked to correct other users’ posts. In a few months I returned and tried again and I found that I liked to correct other users’ posts.

More natural: "enjoyed correcting" rather than "liked to correct".

I worked hard giving correctingons and answering questions, but I thought it was strange (somebody would think it wasmight seem strange) that I only corrected and didn’t published any posts. I worked hard giving corrections and answering questions, but I thought it might seem strange that I only corrected and didn’t publish any posts.

"To correct" isn't usually used intransitively.

I reluctantly started to write and find outound that I liked it even more than correcting. I reluctantly started to write and found that I liked it even more than correcting.

For a while, I was an eager writer (for a while). For a while, I was an eager writer.

The site closed signing upto new users and its community gradually declined. The site closed to new users and its community gradually declined.

Or: "stopped allowing new users to sign up". This sentence would sound more natural with a transition at the beginning, since it is a huge piece of bad news! For instance "However, the site closed..." or "Unfortunately, the site closed...". You could also add an adverb like "eventually" or "ultimately" between "site" and "closed".

The site was closed in February 2024. The site was closed in February 2024.

I look at this post and it seemeds uncomplete to me. I look at this post and it seems uncomplete to me.

English isn't my first language. However, I once passed a Cambridge exam (FCA) with an A, so I consider myself competent enough for making this correction here :)

I look at this post and it seemed us incomplete to me. I look at this post and it seems incomplete to me.