I use my own lifestream plugin to feed my blog page with activity from other sites.
A (long) while ago HTTPS feeds stopped working, basically due to certificate trust issues.
Now the lifestream plugin uses WordPress built in functions to perform HTTP requests.... and this was not something I wanted to change. It's taken a bit of exploring to work out why the default configuration did not work... and then find the best way to patch it.
Eventually I found out that you can set the PHP_CURL CA Path in php.ini using the curl.cainfo directive. On CentOS the "well known" CAs are stored in
/etc/pki/tls/certs/ therefore the fix was quite simple, add the following to
curl.cainfo = /etc/pki/tls/certs/
Job done! Now HTTPS only site (like github) lifestream nicely!