For some they do yes.
I used to work for one of the major ISPs (about 5 years ago), and designed a system where traffic could be "snooped" from an individual's specific internet connection, then stored for evidence later. I also worked on a similar system that intercepted and blocked child porn, based on data from the internet watch foundation.
However, it could only be used if a judge ruled that it could be, this wasn't something that was simply turned on at the will of the provider, to collect data - it was for things like terrorism, or whatever.
A lot of this stuff has existed for a while, and is in the public domain if you know where to look, or are interested.
That said - by having a social media account, people are probably handing over insane amounts of personal data to a social media company. Anything an ISP does - is likely to be practically non existent in comparison.
I have no idea about any ulterior motives, or conspiracy theories, the system seemed pretty benign and sensible.. Whether this tech will be used to collect data to make money, in future - I have no idea.