Here is a trick on how to annoy your (mobile using) friends on Facebook: post an update that has a very long URL (without any blank spaces, etc.). The moment you do that, your friend’s screen will try to fit the entire URL in one single line, without horizontal scroll, thus reducing the font size drastically. Your friend needs to deal with an awkwardly long scroll bar, even after zooming to the right size.
I witnessed the same on my blackberry when one of my friends posted such a long URL. I had to just wait till his post gets pushed out by other recent posts.