If the referral link is not active, nobody can earn extra points by referring others. Forum posting and article writing are the best two options of making money from this site. Members of this site is not so active in other kinds of activities.
If you have a website or blog, you can make lots of money from google ad-words. But getting approval from this site is not easy. There are some terms and conditions for getting approval. But so many people are making decent income from this site.
Scope of online earning for us are become less day by day. At present only Boddunan is working site for article writing and discussion. Some PTC sites are also paying but status of these sites are not sure. I am working with one survey site but it is much slow in paying I received check in March 2014 and one more payment is due from March 2015, but still I did not get check. It is satisfying thing that site is replying.