tact is not my strongest suit
There really must be a polite way to say "thanks for going to such a great effort to inform me about something I already knew", right?
(In English, by the way. There's no point in even remotely trying to convey it in Japanese.)
(In English, by the way. There's no point in even remotely trying to convey it in Japanese.)

no subject
most things that it happens for, this probably isn't an issue, but there are a few where I just never posted about something on my blog itself even though I knew about it... and then someone will send me a long comment or a long email out of nowhere to tell me about it, and in my brain I'm like "...yes, i KNOW that" but I hate to type anything for fear of being rude.
Actually, the worse ones are when I *DID* post about the thing in question, but the person writing to me simply kind of found my blog and was like "omg! you like Japanese baseball! let me share with you everything I know about it!" without actually reading or searching first. In those cases I'm usually just like "Yeah, I know" with those words being a link to where I posted about it, without saying anything else.
(It's funny, because I've gotten to the point where *I* tend to preface comments on other people's blogs like "...you probably know about this already, but...")