[mashup] by itself should show only current posts, which would be type ‘post’ and limited to 10.
You can use [mashup query="all"] to show all posts, but that can be slow or cause the query to run out of memory. I would suggest tagging or categorizing the posts with maps.
If that doesn’t help, a few tests might narrow it down:
1) Enter [mappress] on one of your posts. Do you see the map?
2) Try [mashup query="p=1234"] where 1234 is one of your post IDs. Do you see a map?