@asklemmy can i post from Mastodon to Lemmy ?
Yes, but keep in mind hashtags look awful on Lemmy and the first line of text of your toot becomes the post title. A lot of mastodon posts onto Lemmy are really ugly and borderline incomprehensible. So be careful.
Where would I even find Mastodon content, being logged in on Lemmy?
The instances / servers don’t seem to auto-populate here, so would I need to subscribe to something?
It doesn’t really work the other direction. Mastodon users can post and comment on Lemmy communities by @ ing the community. There isn’t a way for Lemmy users to browse hashtags or users from Mastodon. Even if you click on the user profile for a mastodon user from Lemmy, it’ll only show you the stuff they’ve posted and commented on Lemmy instances, not the full activity of the account.