QSlider (https://axcoto.com/qslider) that enable you to control presentation slide on http://speakerdeck.com and http://slideshare.net directly on your iPhone. I think the app feature is unique and very useful to speaker, or student.
One of unique feature is that you can control right on lock screen. You can see demo on my site: https://axcoto.com/qslider
SlideShare recommends my app on their blog too: http://blog.slideshare.net/2014/02/06/control-slideshares-from-your-phone-with-qslider/
QSlider work with SlideShare or SpeakerDeck, meaning you must upload your slide to either of these service. This sound troublesome at first, but it give you much more flexible: you don't need to bring your slide with you in an USB or send email to anyone, you don't need to use any special software (PowerPoint, Keynote) to open or view your presentation slide.
Here is workflow before:
Create presentation slide with PowerPoint and Keynote
Come to a conference or meeting. Bring laptop with you, or use the other laptop that has PowerPoint or Keynote instaled
Open it and control with a wireless mouse or a special presentation remote (this usually cost more than $30 bucks)
Here is workflow with QSlider:
Create presentation slide with your favourtie software
Upload to SlideShare.Net or SpeakerDeck.Com. Both of these service are free and hosting millions of slide.
Come to meeting. Open web browser (Firefox, Chrome, Internet Exploer), visit your uploaded slide.
Use your iPhone to control
QSlider support normal jumping: backward, forward, beging or end. Or you can use a slider to jump quickly between slide. A screeshot is also showed up on screen for your convenience.
The collest thing is you can control right on lockscreen. If you ever use Music app or iPod app, you love the ability to control right on lockscreen. QSlider works exactly same way. You don't need to keep unlocking iPhone during a presentation.