LinkedIn can't seem to decide what it wants to be. A while back, it added Facebook-like features that everyone (including me) used for a while, but it takes time to sit on LinkedIn and read everyone's posts. Over time, the traffic on the groups has declined to the point where it is nearly non-existent. I know that some very large LinkedIn groups have a lot more postings, but my view is that if you have lots of time to write and respond to stuff on LinkedIn, you are probably not doing your job.
I got a message from someone today, and when I tried to reply, I found that LinkedIn had again changed its interface, and unless I missed it (entirely possible), there is now an instant message style interface. It took me ten minutes of clicking around a bunch of mostly blank screens before I was able to respond to the message request.
The new interface was (is) obviously buggy. So like many other Internet-based services, as these companies fiddle with the interface and the features, the software just becomes harder to use.
Once Skype was purchased by Microsoft, we noticed a gradual and steady decline in the quality of the software. As an example, we used to use the file transfer feature all the time (i.e. several times a day). We are back to emailing files around or putting them on the shared server (both less convenient) because the Skype file transfer fails so often we now just ignore it--if you can't predict when it will work and when it will fail, it is useless.
Apple has similar problems. In their desired to make all their Mac apps "the same" on the Mac and on iPads/iPhones, they have not only removed features, screwed up a wonderful interface, and introduced bugs. And they don't really seem to care very much. Steve Jobs has to be spinning in his grave.