Strange! New (blog-) content is not visible to authenticated users, whearas older content of same type is.

Hello!

Since today i face a strange problem: I let my users write blogs and categorize them, displaying the categories in different views.
Yesterday I created some new content-types - but it all seemed to be working and without change.
Today I notice that normal authenticated users don't see their new blog-entries in their profiles, but i (as superadmin) can see it. And similar it is with the views: normal authenticated users can't see their new content in the views, but i (as superadmin) can.
Older content in the views all can see - authenticated users and me.

I checked the roles settings (they should be able to see all views and contents); I also checked the views, if i changed the role-settings, but nothing. This also affects the standard 'new blogs'-block (and also this i checked, if it is restricted to some roles).

In the logs I don't find anything that could show me the problem. I didn't install new modules, etc. Only was playing a bit with panels today (but don't see a conntection there to my problem).
Does anyone has got an idea - don't know what to try anymore!? It would help me really much!

Thank you,
Stefan