So I don't get it, are you pro-Google / anti-Google; pro-Twitter / anti-Twitter? I must say that some of your positions on this are confusing to follow.
Being a teacher and not a corporate board member or stakeholder, I could give a darned less about the competition between Google, FB, and Twitter.
Except in how it effects the growth of a free Internet and global access to information.
I've cringed at many of Google's decisions, but think that Google Apps is a great platform. I've cringed at many of FB's decisions, but I think social networking is producing a watershed event in the way societies work and I think perhaps more than anywhere else on the Web, FB may be the source of that watershed (the watershed not being FB itself, but rather the concept of social networking of such a grand scale). I find Twitter to be tricky and cliquey, but I think it's the beginning of a new type of intelligent human network (and talk about potential for 'grand scale').
Most importantly, so long as they exist, and so long as they are useful, and so long as they continue to evolve, I will continue to use, experiment with, and mash up any and all of the resources the Web offers for classroom use and fresh new ways of learning.
Be the disruption. Use technology however you want. The students are the real stakeholders. Change your classroom. Change the world.