For some reason I'm able to say "I don't know" to coworkers and superiors at work with no problem, but I have a much harder time online where it may affect future employers' opinions of me.
I agree. I think, at least for me, it's because I know my colleagues know my overall capability, so admitting I don't know a specific thing isn't a big deal because I've already proven I'm capable of overcoming any specific gap. But to strangers, perhaps that may be all they know of me -- that I don't know this one thing. There's no preexisting relationship or past body of work (in other words: no trust) to balance that gap out or put it in perspective.
I think this is objectively mostly a silly and counter-productive worry. But I still feel it.
- I blog with my real name, which includes an uncommon first name. It's easy for hiring managers to search the web for.
- My blog is linked from the website I host on the domain name I use for my email address, including for job applications. Anybody I email is likely to follow that thread.