[akerl_]

Defensive patents are effective against patent trolls, because if you have your defensive patents covering the things you do, you can bring those to court as proof of the origin and creation date of your ideas, should the patent trolls come knocking.

[noonespecial]

Yes you can bring them to court along with your million dollars and 6-8 months of time and aggravation. You'll likely "win".

[sitkack]

But if you want to defend against trolls and do not seek your own patent monopoly, patents don't make sense. Slow and expensive. Other means are vastly cheaper.