Posting a bounty for How to navigate a lot of tabs in Google Chrome on iOS (iPad) was my first activity on the StackExchange site 'Ask Different', and apparently I didn't get any reputation bonus for joining that site (as usually seems to happen) because my reputation there shows as 1. As a result, I can't comment to answers (or the question itself) on the question I posted the bounty for.
Is it a bug that I didn't get the reputation bonus when I joined a site in this way? Because there's what appears to be a +100 message stuck in my StacExchange inbox--it has a completely blank subject--and nothing happens when I click on it.
Regardless of that, if you think about it logically, shouldn't sponsoring bounty on an affiliated site trigger a special case that ensures you can at least comment in the thread?
[edit:] As I explain in an answer below, I mistakenly thought that a person's reputation was fluid across all StackExchange network sites. In fact, it's tabulated separately, and reputation from one site cannot be used at another.]