there’s no way that I immediately see to look over -all- public posts to see where the activity is

entire list is currently populated with porn

That sucks :( But it can also be used to illustrate an important point about the sort of essence of scuttlebutt, which is being pull-first. You must be “pulled-in” to join social circles. This means it’s harder to get into any given circle, which can be both a good thing and a bad thing. Once you have established a presence on the network (meaning you have at least a few people follow you and replicate your feed) and are not reliant on public pubs, chances of getting unwanted porn are really quite low. It’s a great example of what I would call grassroots moderation, where the task of blocking unwanted actors and content is spread out across all users in a way.

If you want people to replicate your feed you may want to introduce yourself on #new-people channel, at least that’s where the introductions happen on the mainnet.

Is there some way to link an account between devices

As far as I’m aware there is no good way to do this. What people often do is they will make another feed (“account”) on their phone and ask their friends to follow that one as well.