For scientists, personal opinions as human beings clash at times with ethically demanded objectivity. As a blogger, there is a better match, as it is supposed to be a personal outreach. Still there is the authenticity vs. publicity issue, if it is done for money or pride, rather than for sharing opinions.
Humans want to live, act and change the world – more or less intentionally. If there are intentions to make the world a better place, what should we do as scientists? Should we disseminate our findings in blogs, reach out to decision makers or engage in politics to "really" make a change?
There is many hamster wheels one can waste energy in, and as a clockwork, society has many of these wheels and depends on a multitude of them. Not everyone can be president of the US, influencer, or World Champion. The more are trying, the lower get the chances of having an impact for each. A question might be what you can do best – if you are a show(wo)man with low integrity, then running for president might be your call. But we also need farmers and nurses!
As a scientist, you are supposed to be objective, act ethically and generate knowledge for everyone. Strong personal opinions and lack of openness as well as narcissism might help for a scientific career, but counteracts objectivity. We need to be aware of normative aspects and the limitation of the knowledge we gain. For example, reducing greenhouse gas emissions will help to limit global warming and related environmental impacts, but defining this as being a good thing is normative and highly anthropocentric – even if we are concerned about biodiversity. Is it bad to have the world and mankind destroyed? Definitely for life on earth, but who cares in the universe? And what exactly is this universe, and how was it created?
We finally need answers from belief, which is not a very scientific reference. However, it is very important for most people and especially bloggers. It is the basis for motivation and can be very helpful - or even lead to disasters. Don't we all contribute to destructing our world, even if we are trying to save it? Does it matter and who can answer this?
Science is designed to answer specific questions, and insights are generally valid until proven wrong. The truth is only possible with context - at max the current knowledge. Beyond truth, there are opinions, which can convince people by use of selected truths at best. Science becomes obsolete when we know everything. Before this point in eternity, we need more science, opinions, conviction, implementation and revision of all these acts based on the new truth, as it is dynamic.
In conclusion, we should be modest and realistic concerning what we can change with our capapilities. If scientists become blogger about theirs research, they start concluding beyond scientific results, simplify messages or neglect limitations of the results, and thus convey opinions. If we engage in decision making, we become politicians or managers. We can obviously be more than just scientists, but as such we should keep focus on high quality research. In a specialized economy, we can provide this information to professionals that interpret the data for normal people and decision makers - and there is clearly a need for more of these. If we act in several spheres ourselfes, we should clearly indicate, which hat we are wearing, and make sure not to loose focus on whatever we can do best: Science, Blogging or being a World Savior!
This is your personal assessment, and it should influence your career plans. However, be aware of the normative aspects when assesing situations or other people - and don't be smug!