Your earlier comment sounded like you were saying that a company adopting this patent hack would be hard to sell to other investors. Isn't selling companies to other investors what an early stage VC does?
If I were investing in a company that had these things, I would be concerned that the patents were now no longer licensable - that their value had been decreased by waiving some of the rights granted by the patents.
In certain situations, I could see investors trying to undo this agreement so they could unlock that value. If the value is great enough, they will try really hard (and given how vague this agreement is, I bet they'll succeed). That's all I'm saying.
In the end though, I don't see how this agreement is anything more than twitter saying "we won't sue people over patents, and we won't sell them to people who will". I don't see that as particularly significant. Just that twitter isn't pursuing licensing revenue as a strategy.
