I feared my comment would come across as a disguised ad hominem attack (thanks I didn't know there was a name for that!). But if you read the whole comment, it should be obvious that it's not in fact Tu quoque because I do address Sachin's position. I used Posterous as an example to argue that people don't make software just to innovate; there are other things to consider such as market trends and user needs.
You are right, I don't think it was an ad hominem, besides you made a valid point about Posterous. I just read the wiki stuff today and couldn't resist.
