Original: In certain cases Instant Messaging involves additional features, which make it even more popular, i.e. to see the other party, e.g. by using web-cams, or to talk directly for free over the Internet.
Simplified: In certain cases IM involves additional features, which make it even more popular, i.e. to see the other party, e.g. by using ((web-cams)), or to talk directly for free over the internet.