It is primarily a bookmarking application, but the feature list indicates you can also ". . . use it for micro-blogging (like Twitter), a pastebin, an online notepad, a snippet repository, etc."
IndieWeb community members who are using it on their own site:
- Johannes Ernst is using it since he moved from delicious.com, and he's not looking back!
- Élie Michel uses it too.
Adding a bookmark in Shaarli has it send a webmention to the target URL.
Actually, this function has not been merged to the master branch yet but is available in that fork.