This seems like a common pattern

1. Realize you need to make a lot more money (to meet investor expectations, pay for the fat the company has accumulated, etc)

2. Panic

3. Apply dark patterns (http://darkpatterns.org/)

4. Something better comes along and eats your lunch

5. Repeat.

It's sad because imgur was originally created as the "something better".

SourceForge got bought by new folks who reversed all the misleading ads and bundling stuff:

https://sourceforge.net/blog/sourceforge-acquisition-and-fut...

To be fair, I think those are usually the fault of malicious ads getting into whatever ad networks imgur uses and they usually get rid of them fairly quickly. They used to pop up every few weeks but I haven't seem them recently (in my experience as a daily imgur user for the past year or so).