There are already countless chatting software (such as WhatsApp, Skype, Discord, Facebook Messenger), but almost all of them are non-free software based on central servers, and their security and privacy are not guaranteed (any chat history of you will be sold to various companies). Many of them claim to encrypt communication content, even with end-to-end encryption, but when a platform is proprietary, there is simply no way for others to verify that it is as secure and private as it promises to be. Of course, there are some really safe and reliable ones, but they are frequently blocked by governments of various countries and cannot continue (such as Signal, Telegram).

Starry Night is the world's most powerful astronomy simulation software and most professional astronomy telescope control software for Windows and Mac platforms for now. It is built specially for astronomy enthusiasts to best meet the needs of any amateur astronomer and any advanced observer. It makes space observing as fun and efficient as possible, and helps astronomy enthusiasts take their astronomy knowledge to the next level.

Google Pinyin (AKA: Google Pinyin IME, 谷歌拼音输入法, Google拼音输入法) is an excellent Chinese and English input method program for Windows and Android platforms, developed by Google China Labs in 2007. Google released Google Pinyin V2.0 with a lot of new features and improvements in 2008; released its Android version in 2009; and released Google Pinyin V3.0 with English writing assistant feature in 2011. Although its development stopped long ago and the product page was finally removed in 2019, even today (more than 10 years later), it is still the #1 app of all its kind.

Google's Chrome browser already dominates the entire web browser industry for a long time. This thanks to its extensive library of browser extensions, which can satisfy almost any of our needs. However, it can be difficult to find the best or most suitable one for a particular purpose in this vast library: 1) You might not know how to find them via appropriate keyword; 2) There are too many similar plugins for the same function, and trying them one by one is so inefficient.

Nmap (short for Network Mapper) is a free and open-source network security scanner for large networks. It was originally developed by Gordon Lyon (Fyodor Vaskovich) for Linux in 1997, later gradually became one of the most popular network discovery and security auditing tools on multiple operating systems with the participation of many volunteers in the open source community.