I've developed a new ratings interface option to enable teachers to create a customisable 'like'-style button as an alternative to the standard select menu, which doesn't work well with single-item scales (now supported in Moodle 2.8 onwards). This was done in response to a suggestion from one of our postgraduate distance learning students:

"Even though I am not a fan of Facebook, I now think that a button like the 'I like' button, is missing in this Forum. Especially if you simply agree with something, but don't feel like adding a post with the words " I totally agree with you" or "thank you, I found it useful", "good thinking".
If such a button would exist - and of course, if using it consciously and in a responsible way-, then some posts which have probably not received a reply, feel that they have been at least read. Besides, one could check who likes or shares the same concern/ issue, which in turn can increase students' motivation."

The button uses AJAX by default, but degrades gracefully if JavaScript is disabled. It was developed primarily for Forum posts but also works fine for Glossary and Database entries, and can be extended to support any other activities that may support ratings in the future. It can be used with any single-item grading scale (e.g. Like, Useful, +1, etc.) and will create a new scale automatically if it doesn't already exist, based on the string entered by the teacher into a text field in the activity config form. The teacher can also choose from a selection of icons to be displayed on the button alongside the string.