Here are some ideas. Others may add more ideas.
1. what is the essence of TC -- how is TC distinctive from other distros?
Tinycore Linux begins as just a basic operating system, without many applications. Additional applications can then be installed.
Most other operating systems have many applications installed by default, some of which many people never use. With Tinycore you can choose which applications to install, and not have those you don't use.
Tinycore can be set up for any type of use, by installing the appropriate applications.
Quick Startup
Tinycore can be set up to start quicker than most other operating systems.
Minimum RAM Use
Tinycore can be set up to use less RAM than most other operating systems.
Frugal Install
Tinycore is installed frugally.
Most computer operating systems are installed conventionally. When installed this way, files throughout the operating system are modified as it is used. As a result of malfunctions, user error, malware, or just because the operating system is imperfect, files may becomes corrupted, and it may not work properly, or even work at all.
If an operating system is installed frugally, operating system files cannot be modified, so they cannot become corrupted. However, personal files and settings can be saved.
When the operating system starts, it is loaded to RAM, and runs from RAM. What is in RAM can be changed, but the original files can't. When the computer is turned off, everything in RAM is lost. When it is started again, the operating system is loaded to RAM again, so it always starts in a pristine state.
If Tinycore works the first time, it will work every time.
Quick Installation
Tinycore can be installed much quicker than most other operating systems.
Install on Hard Drive or USB Drive
Tinycore can be installed on a hard drive or USB drive.
Run from CD
Tinycore can be run from the CD. While running from the CD, you can install applications, and save files and settings, on the hard drive.
Computer
Tinycore can be run on new, high performance computers.
It can also be run on older, slower computers. Minimum performance requirements depend on which applications you install in Tinycore. Most applications will run on a computer with 256 mb of ram. Tinycore can be run on a computer with 128 mb of ram, with selected applications. It may not be worthwhile for most people to run Tinycore on a computer with less than 128 mb of ram, as even less applications will run. The absolute minimum to run Tinycore is 48 mb of ram.
The hard drive size required, also depends on which applications are installed. Tinycore is approximately 10 MB. Applications require additional space. It is ideal to also have a reasonable amount of space to save files.
Transfer to Another Computer
Whether installed a hard drive or USB drive, it can be transferred to another computer, and Tinycore can be run from that computer.
This is handy for people testing computers. If you have Tinycore installed on a hard drive, you can just connect the hard drive to the computer, and turn it on.