I thought it was like Facebook or Google+ activity streaming automatically, but it seems not, I have to manually refresh the page to see new activities, is this normal?
And I'm not sure if this is related to cron, I keep receiving cron email like below:
Yes, we took a weekend that's why you didn't receive any answer.
Currently, newsfeed activity updates by page refresh only.
The message which you receive from your cronjob doesn't contains any errors/warnings, so, you may disable email notifications or contact your hoster provider about this output and how to disable it.