Great

builtwith を使うと、ページが利用している Web解析サービスや広告のピクセルタグなどのサードパーティタグだけでなく、HSTS などHTTPプロトコルも分かる。また逆に trends.builtwith.com ではそれらの技術が使われているサイトを知ることができる。日本 国内向けなど一部サービスの未対応タグを提出し、拡充に協力したい。

Sometimes it is just as easy to right-click and view the source of a page, but I find many things new when I use BuitlWith... I also was, at first, not that impressed with what BuitWith is doing as far as the model of their website resource User Experience; but once I started using it for what it is, I found many technologies that were very interesting to me that I would have otherwise just passed by or never found.