[roblabla]

The license means that even if SO changes its policy and puts up a paywall, a clone can come up, use the knowledge already present on SO that was scraped.

This means that even if SO puts a paywall, the knowledge gathered there is not lost. And this, IMO, is a very, VERY important aspect of StackOverflow.

As far as search goes, I didn't even know SO had a search function. I see nothing wrong with letting google handle it. Adding a search engine to your website is hard and takes time.