Mindmeldr is a live group interaction framework, allowing you to present slides, photos, or questions to a group of users over the internet using a browser. Members of the group can respond instantly using their own browser, or by "tweeting" from a mobile phone. The responses can be in the form of text messages, graphical annotations (i.e., marking a point or drawing on the slide), or answers to multiple choice questions.
You can use Mindmeldr as a web-based Classroom Response System (i.e., like "clickers") to assess students and receive instant feedback using traditional multiple choice, as well as visual choice questions. Students respond either using a mobile browser, or by creating a Twitter account and texting their responses.
You can also use Mindmeldr as a collaborative presentation tool, by uploading a set of images as a presentation and allowing your group members to view the presentation synchronously using their browsers, while annotating it graphically.