Rating/Voting and Tag APIs, do they exist?

Everyone loves to display Digg/Tweet/Like badges on their websites, and the Disqus Comment System is starting to take over.

_{(source: disqus.com)}

_{(source: digg.com)}

The benefits of those systems from a developers perspective are:

1. You don't have to program the complex, fully-featured logic that those seemingly simple systems require.
2. You don't have to handle the database scaling or application performance issues that might arise if you built a comment/like/digg look-a-like and it became popular
3. All of the data collected becomes part of a global collection of data.

I'm wondering, do you know of any services out there that accomplish the following (each number in the list is a hypothetical different service):

1. Allow you tag some item on your page. Maybe a javascript api that allows users to click "tag this" and they can add 1-5 tags for your blog post, and the service stores your blog post by an identifier (url, database id, etc.), and the tags. Would work exactly like Disqus but for tags.
2. Allow you to vote or rate an item on your page. Similar to the StackOverflow voting system, a service with a javascript api that created a widget for associating a piece of content by id with votes.

I mean, have these things not been invented already??? Or have they been tried and failed? If the comment problem has been solved, it seems crazy that tagging and voting haven't been solved in the same way.

Is anybody working on this, or is there something out there like this already? Or do you have a workaround for making the current systems out there wor开发者_Python百科k like this?

Looking forward to your ideas.

Note: I am very familiar with all of the libraries out there (i'm a ruby guy, so all the acts-as gems, etc.) to implement these things yourself. I am asking this question to try to find a fully featured system that is just as easy to use and scalable as the services listed above, requiring only a javascript file. I have scoured the internet for them with no luck, but then again new services are popping up every day.

Try these:

ajaxful-rating

acts_as_taggable_on