Tweet Overlayer is a free Chrome extension developed by hjmkt. It falls under the category of Browsers and is classified as an Add-ons & Tools subcategory. This extension allows users to retrieve tweets about any web pages they visit and overlay them on their browser window in a Nico Nico Douga-like style.

With Tweet Overlayer, users have the option to specify certain keywords and have tweets related to those keywords flow on their browser window. For example, users can specify a specific hashtag and have real-time tweets displayed on top of live videos from platforms like Ustream. Additionally, users can customize the color and transparency of the tweet text.

This extension provides an interesting way to stay updated with social media conversations related to the web pages you visit, adding a dynamic and interactive element to your browsing experience.