[Debbie]

I believe the posts can be read by anyone worldwide, meaning you don't need to be a member to read the posts.  You need to be a member to post.  If this is in fact the case, then many more lurkers than posters would be expected.  It would also be prudent to use a name and photo which can't be traced.

I have to say, I'm not sure I'm comfortable with anyone, from anywhere in the world, being able to read my posts.

You are correct.  This is a public forum.  The posts can be read by anyone.