Some of the biggest tech IPOs, namely LinkedIn, Pandora, Groupon and Zynga, have been the top stories on Wall Street this year.  It’s an indication of the tech sector, as well as the global market overall.  While many aspects of our economy continue to struggle, certain areas of tech seem to flourish at an unstoppable pace.  It’s cause many to say we’re in the midst of another bubble, but bubble talk is always just talk, until something goes “pop.”  Until then, we can only revel in the continued success of growing social services, which gain value through our ongoing support as consumers.

An interesting infographic can be found below, but here’s a brief recap of IPOs in the social tech sector.

LinkedIn filed for an initial public offering in January, and the IPO occurred on May 19.  With shares initially priced at $45, they rose to $122.70 in the first day of trading on the New York Stock Exchange under the symbol “LNKD”. The company is now worth more than $9.5 billion.

While Pandora‘s IPO is worth $2.6 billion, it is not as profitable as LinkedIn. Its loss in 2010 amounted to $1.8 million on $137.8 million in revenue. Pandora is now looking to sell 15,736,600 shares at a maximum offering price of between $7 and $9 per share. That means its IPO could be as big as $141.6 million.

Then there was Groupon, which filed with the Securities and Exchange Commission to go public in a $750 million IPO. For the full year of 2010, the company’s revenue totaled $713 million, up an astounding 23x from 2009.  However, the company’s revenue in just the first quarter of 2011 was $644 million, showing just how fast Groupon continues to grow.

And after months of speculation, social gaming juggernaut Zynga has finally filed for an IPO that could raise upwards of $1 billion. The company has 60 million daily users, 232 million monthly active users, and its revenue in 2010 reached up to $597 million.  The company was worth $4 billion in May 2010, but its value doubled for more than $10 billion in February of 2011. The IPO could value Zynga as a $20 billion company.  Zynga is the company behind hit games like FarmVille and CityVille.