I think Twitter they should go one step further and form a pool of companies which bring in all their patents and: 1) If you join, you are not allowed to bring any other patent lawsuits against other companies. 2) If you get sued, you are able to attack the sueing company with all the patents in the pool.

Or even add: If you are licencing a patent to another company, the licencing is void if that company attacks another company.