Shared seedbox means a seedbox which is similar to a shared webhosting server which has limited options.
Shared seedbox is generally a cheaper option where you generally don’t need a root access , the shared seedbox generally provides you with a web GUI inter phase, which is just like your torrent software , and its just a web version of it running, you can visit this Graphic user interphase with a link or ip address your seedbox provider would provide you.
The important aspects to keep in mind while getting a shared seedbox is as follows.
1. How many people are sharing the seedbox server.
2. Whether the speed is shared or whether each shared slot has its own speed allocated.
3. The amount of RAM provided
4. HDD space and how many people share it .
5.HDD type.
6. Processor type , if your shared server is shared by many and has a low end processor , it will easily reach 100 % cpu and have a glichy seeding and downloading , which is definitely not recommended.
You could check the below shared seedbox providers which have been tested for performance and are at very competitive prices.