I have install aem communities v1.8.557 with all required hotfixs as explained in Deploying Communities - docs.adobe.com .
Also verified that tunnel service is enabled and replication & revers replication is setup correctly.
When ever i registered user on publisher it get synched to author but content created on publisher like comments, blogs are not getting synched to author.
Please provide your input or share any documentation.
Tunnel service is only used to sync user between author and publish environment.
To sync the UGC, you need to use either of MSRP, DSRP and ASRP. Here is the doc for srp configuration