Advertising Investments

I am currently going across various websites to collect the PE/VC investment deals, When analyzing these deals it is quite surprising to see that IT boom is not over as yet. It is still in disguise of Advertising boom. May be I am reacting too much and have no doubt that Google is excellent innovation based company but it is primarily a Advertising company.

So when the deals were analyzed, one might say that all these social networking websites are getting another round of funding. I was just wondering is there a real need to invest this hard earned capital in "Social Networking" / dating websites which earns majority of revenues from Advertisements?

So I am just trying to understand the difference between 2 social networking dating websites including their competitive advantages except the ad-spaces, inventories and other so-called efficiencies. There has to be some limit in senseless investments. This shows people have now become too greedy to explore various avenues and going in for some short term quick gains.

There are several social economic businesses lying around where there is still paucity of funds. I am not saying to invest in businesses with bad economics but essentially investments are required in healthcare and other tangible businesses which add significant value to the society.