Users and mods are both right here. Asking for plugin recommendations will end up having endless open questions filled with plugins that not always are verified. This can also open a space for spam, since mods can't check each link or plugin and verify if it's safe (if not on the repository). So, to prevent StackExchange from becoming an Ad-house, this is necessary.
What To Do?
While there is no official way or silver bullet, there are some... some ways that can be helpful.
Since Quora has less strict rules about these, you can consider it a place which you might be able to find what you are looking for. It's not as expert-ish as SE, but it can help.
2- WP Begginers
WP Beginners is a well known website that had tremendous amount of articles about plugins. Sometimes they even offer both plugin based and code based solutions, in a single article. While I don't like plugin based answers personally, it can be life saving in some cases.
3- WordPress Plugin Repository
Yes, it's as simple as that. There is a search feature in the repository itself, that is overlooked most of the times. Looking through the tags is quick, and you can safely choose a plugin based on ratings and reviews.
4- WordPress' Support Forums
This is another place to ask your WordPress based questions. As they claim, no question is considered bad on the support forums, but still they have their own "How To Ask a Good Question". Take a look into it, and strive toward happiness.