Strikethroughs

How are people doing those? I haven’t figured it out and it is driving me crazy!

The del tag. For instance,
[noparse][del]this[/del][/noparse]
produces
[del]this[/del]

Oh thanks. [del]test[/del]

Most of the time, if you want to know how someone achieved a certain effect, just click the Quote button for that post, and their coding will be revealed in all its glory.