It's a very interesting move. I guess the calculation (apart from real benevolence, which I don't mean to undercut) would be that the good will and good press, affection from idealistic engineers and the resulting hiring and retention advantage, and the effect on the rest of the patent landscape (over which they have no direct control) is worth more than the patents themselves.
The thing is, how that plays out depends on whether or not other companies agree to change their behavior. If it's true, as another comment says, that they will allow Apple to use the pull-to-refresh patent, for example, that's some clear leverage lost. If no one else makes similar moves, won't Twitter be at a disadvantage in the context of the "patent wars?" Will the other advantages I listed above still be worth it if the patent landscape doesn't change? Does this effect the value (especially as a potential acquisition target) of Twitter? I don't know enough about their portfolio of patents to know how valuable there patents might be.
In any case, it's at least something new-feeling in the story of software patents. Hopefully it will have some positive effects.
EDIT: Also, hearing all this talk of "defensive" patent use makes me think about Intellectual Ventures; does that sort of thing count as defensive under this plan?
One possibly self-interested effect could be that it may make engineers more willing to go along with applying for patents. A lot of engineers feel very squeamish about software patents, and try to avoid applying for them or letting themselves get coerced into applying for them. A commitment by Twitter that they won't use them offensively w/o the engineer's permission may make recalcitrant engineers more likely to submit/sign the relevant documents.
I said specifically I'm not intending to undercut their motives. Even if that's true, I think it's worth understanding how it impacts then strategically.
There also a question of the legal aspect of letting other companies infringe for a while and then trying to start litigation against them (e.g if they broke condition 2b).
How would courts view this? Or does it not matter?
I don't think Apple could use the pull to refresh patent without fear since they would fall into the 'sued people offensively in the last 10 years' bucket referenced, no?
The thing is, how that plays out depends on whether or not other companies agree to change their behavior. If it's true, as another comment says, that they will allow Apple to use the pull-to-refresh patent, for example, that's some clear leverage lost. If no one else makes similar moves, won't Twitter be at a disadvantage in the context of the "patent wars?" Will the other advantages I listed above still be worth it if the patent landscape doesn't change? Does this effect the value (especially as a potential acquisition target) of Twitter? I don't know enough about their portfolio of patents to know how valuable there patents might be.
In any case, it's at least something new-feeling in the story of software patents. Hopefully it will have some positive effects.
EDIT: Also, hearing all this talk of "defensive" patent use makes me think about Intellectual Ventures; does that sort of thing count as defensive under this plan?