It's nothing new. Small companies get swallowed up by larger companies because they are struggling or because they bring enough value to allow them to "cash out" and join the bigger entity.
For some such as Yammer or Instagram, being eaten by the bigger fishes of Microsoft and Facebook was a welcome change that helped many of the employees get a big paycheck. For others such as Digg, it was an unfortunate end to a long but eventually unfruitful run.
There are times when the big and little fish are similar, such as with Tagged and hi5. One was on its way down having not fully switched in the wake of Facebook's domination in the niche while the big fish made a pivot that allowed them to become the premier player in the realm of social discovery. They were just rewarded for their efforts with another round of funding, something you don't see too often for profitable Silicon Valley companies.
The infographic below designed by social media firm Hasai shows the scope of the big and little fish feeding on each other in the ocean of tech acquisitions so far in 2012.
Click to enlarge.
Via: Hasai Social Media