The top three social networks (even though Google+ is getting up to speed) are considered to be Facebook, Twitter and LinkedIn. Reddit is a huge site as well. And it won't be news to you if I say that there are a lot of bugs there. Including basic functionality:
- On twitter every third tweet ends up in "Oops, we did something wrong. Please try again".
- On facebook, if you are trying to post something on your page wall, it hangs. If you press "Post" multiple times, nothing happens again, but all the submissions are saved. So when you refresh the page you have to delete.
- On LinkedIn the same as above happens - if you try to post something, nothing happens. With the tiny exception that when you refresh and see the multiple posts you can't delete them, because the "delete" functionality is also not working.
- On reddit you can obviously get shadow-banned by mistake (I was) and nobody can/is willing to do anything about it. You lose your account due to a random factor.