APN's hosts, Ning, are struggling to put right all the problems that have popped up following their system maintenance (!). Glad to see the 'Latest Activity' feed is now working.
To add a post - click on plus sign at top right (if it is not there, you are not signed in - see link at top of page). To later edit it, display the post, and click on pencil at top right.
If you wish to give somebody your contact details, you may prefer to do so by personal message (click on little envelope at top of page, then on plus sign) rather than putting it in a post which is visible to everyone.