Well it's not a post about burning things, but more an inquiry as to what can be done at certain output levels.
First I'll address the point posted that I believe is the most important. That is of blinding someone. Having worked with many lasers of various types and output over the years, my opinion is that and laser of
even 5mW of higher has the potential to causes
permanent eye damage. If you are refering to instant damage power levels, 35mW or higher can do that depending on where the beam strikes inside the eye. If this sounds scarey, I hope so because too many reports of misused lasers are turning up all over the place! Keep in mind that until DPSS green laser pointers became relatively cheap and were able to be modded, high output lasers were not really available to the general public. One thing that the general public lacks is a course on proper laser use theory and safety.
Now for the rest.
Pop a dark colored balloon: ~30-35+mW
Pop any Balloon: Many Watts are needed(for a green laser) to pop a white balloon. You will need an IR laser to pop a clear balloon.
See the beam at Night: ~2mW+(green), a 2mW green laser's beam can still be seen at night.
To see the beam in daylight: ~10Watts(green) to start to be able to see any beam in broad daylight, even then it will appear pretty faint.
Melt elecrtical tape: ~50mW+
Light a Match: ~70mW+ You can start to be able to light a match at around 70mW, this of course depends much on the type/brand of match used and it's composition. You will also need to color the match head black.
hope this helps you with your questions!
It should give you a rough idea of what can do what.