I use yahoo and bing.

i will never use internet

I'll look for another reliable search engine and based my SEO on that search engine.

When the Google search engine turned off, it is sure there are new alternatives。
the world won't stop all function, just because missing anything.

If google closed, Other search engines will take place of Google. All people move to other search engine. I also try other search engines.

If that happens, Yahoo will surely take an advantage from that and it will benefits alot from it. Yahoo will surely be even better than how Google used to be if that happens.

There are must appear another search engine.

than i will go with another search engine after few month