On reddit, one can simply type u/me or r/reddit - I can see mentions of /u/user or /c/community in descriptions but doesn’t seem to mention a sublemmy like a subreddit.
Also, can’t seem to share a Lemmy Profile with their URL like for mine as example.
On lemmy you can tag someone like this:
@mp3@lemmy.ca or /u/mp3@lemmy.ca
and a community like this:
!asklemmy@lemmy.world or /c/asklemmy@lemmy.world
The /u/mp3@lemmy.ca and /c/asklemmy@lemmy.world usage doesn’t seem to be showing any difference from Arctic app.