How can I interact with a friend who is an ICQ user and has connected to a social network, for example Facebook?
Each time your friend updates his status via ICQ, it is automatically updated in Facebook as well. You will see both icons in your Feeds from Friends tab
You can comment on the update, if your friend has allowed it in his personal settings. Comments will appear in ICQ Feeds tab and also in facebook
You can give him "I like it" stamp, but it will appear only inside the ICQ Feeds network (meaning, your ICQ contacts and your friend's ICQ contacts will see it, but not your facebook friends that are not in ICQ