This is about installing on a USB stick, otherwise known as a USB key, USB flash drive, keydrive, thumbdrive, or pendrive. However the instructions will apply to other removable storage media (a memory card or other portable media).
Why put a wiki on a stick?
Having a personal wiki as a wiki on a stick can be useful for demonstrations, personal knowledge management, sophisticated note-taking, or fast installations using a simple copy.
Always stop the web server software and properly eject the stick before removing it.
Take regular backups if you are putting a lot of effort into wiki content, or software configuration/customisation. Remember that a USB key is an easy thing to lose.
If you lose an unencrypted USB key, anyone finding it will have access to the information in your wiki, as the database server is on the USB key.
Encrypt the USB key to protect your data.