"Overall you seem very down on Zynga and Groupon. Note that they have both IPO'd and have far from tanked. They are both in business with no apparent sign of bankruptcy etc."
It's not about bankruptcy. As you say, both Groupon and Zynga will likely continue as profitable businesses for the foreseeable future. But the IPO valuation isn't determined by their ability to stay in business; it's based off their ability to grow. The P/E ratio is close to 80 (Google's is ~20). That means the company is expected to increase earnings dramatically. Do you see that happening? All the data looks like they're plateauing or even trending down. Unless they have something innovative in the pipe, the stock isn't worth the money.
It's not about bankruptcy. As you say, both Groupon and Zynga will likely continue as profitable businesses for the foreseeable future. But the IPO valuation isn't determined by their ability to stay in business; it's based off their ability to grow. The P/E ratio is close to 80 (Google's is ~20). That means the company is expected to increase earnings dramatically. Do you see that happening? All the data looks like they're plateauing or even trending down. Unless they have something innovative in the pipe, the stock isn't worth the money.