iwsearch.netは安全ですか？

You get to this site by fat-fingering a URL, trying to access an unreachable site, entering a badly formed URL, or the like. The site takes whatever information it can glean, and provides search results to match what you're looking for. There is another site like this, net.com, which does something similar, except it displays only advertising, not search results.

You will get redirected to iwsearch.net if you finish typing a site address into your browser's URL bar but press Shift+Enter instead of Enter. This adds .net to whatever you typed, and redirects you there. This is because on many browsers, Shift+Enter is the keystroke combination that will auto-complete *.net addresses (for example, you can type "sourceforge", press Shift+Enter, and you will get redirected to sourceforge.net). The auto-redirect means that this site should be classified as a typosquatter. But at least it's just a non-malicious search site using Google's search engine (it's probably raking in a lot of money through clicks though).