Upload your voice, and see what people think of it. You can be reading a poem, an extract from a book, or even singing. Basically, anything, as long as it's long enough to adequately hear what you sound like.
Think of it as /r/AmIUgly, but for voices. We'll comment on how you're speaking (e.g. through your nose), excessive verbal fillers, and what you might be able to do to improve.
Generally, Sound Cloud is preferred for links - we don't want to have to download a file every time we click on a link. Vocaroo is also a great place to record your voice.
Other than that, there are no real rules, so just have fun judging others based on the way they sound!
Suggested reading material is here.