Yes Linked in communities are more serious and focused. They are not friendship communities even though they are communities to foster contacts among professionals. There is serious exchange of information in Linked communuties.
I actively post in two communities Professors in Management and IIE. I am a formal member of both these professions. I do research and publication.
I advise bloggers to register on Linkedin and become members of appropriate communities and post responsibly. Still as a blogger sometimes you are given warnings for too many posts. Even though you may post one a day, still as you do it regularly others feel it a burden. But keep your cool and follow the suggestions of the group.