I am using gists for keeping lists of things as markdown documents. Being plain text markdown docs makes it way more flexible then dedicated bookmarking solutions.

Gists can be made public and people can leave comments to contribute or otherwise. I don't know of anything more convenient with these features. There is even http://gist.new/ as a shortcut domain.

Some examples:

https://gist.github.com/SMUsamaShah/fd6e275e44009b72f64d0570256bb3b2 P2P file sharing tools

https://gist.github.com/SMUsamaShah/71d5ac6849cdc0bffff4c19329e9d0bb JavaScript immediate GUI libs

https://gist.github.com/SMUsamaShah/6379649c0cbade9abc02b2427bd33210 All In-browser VMs

https://gist.github.com/SMUsamaShah/301994b39334ac2515224b92afb72403 All Hirens BootCD Versions

Can see all my public "List of X" gists here https://gist.github.com/search?o=desc&q=user%3Asmusamashah+%22list+of%22&s=stars