My admittedly anecdotal experience doesn’t support that. The worst perception I can think of would be a (likely older) PI wondering why you’re writing blog posts instead of papers. Blogs are generally seen favorably - they can be a friendly introduction to your work or act as a knowledge base/wiki for how-tos or popular tools.
I know many professors who blog frequently and/or encourage trainees to have a personal website; a PI I work with now has a blog and encourages his members, particularly the junior ones, to contribute for the exposure; and I have multiple grad school friends who blog regularly - so far without negative consequence.
Also, if you want to consider twitter “microblogging”, it only takes a few minutes of browsing scitwitter to debunk the idea that scientists don’t talk about their field online (even unprofessionally). It’s really the only thing they talk about.