Well, in a way, I think he does, I mean he does acknowledge certain events and storyarcs in some issues, but I believe that's all he does.
Why?
Because he said himself, that certain things were not to be and will not be, as long as he was writing the comic.
For example, someone once asked him about the Tails and Barby situation in the comics. And he said, that would never be as long as he was on the book. But he did say he would find a way to put some closure on it.
Now, as far as certain events in the comic goes, like I said he does acknowledge them.
Like recently in issue 212, when Sally mentioned to Monkey Kahn that she has to repair and try to salvage what's left of her and Sonic's Relationship, I think Ian mentions in a yellow box in the panel that slap in 134 that Sally gave Sonic, he also acknowledge the slap in 134 in issue 187.
As far as storyarcs like Mobius Years Later goes, when Ken Penders wrote the book and the story, he said that this was the future, but made us wonder how it came to be.
Now when Ian took over, he continued the story, but also said that this was not the future, but a possible future, if not an alternate future.
Ian does follow that up by having Knuckles father sacrifice his life to save his, instead of dying in a hospital bed, like Ken version had him do. And then recently with what happen to Lien-Da in issue 211.
What I'm trying to say, is that despite all the arguing on how Ian is ignoring past events and all, he does. He just doesn't elaborate on them as much and would rather forget they ever happen, and just start the characters out fresh in his own mind.
That's why I believe he does follow up on stories that other writers did, to not only put his spin on things, but to also put closure on them, so that they will never be mentioned again.
And Those are my thoughts on it.
Rosas, Justin freakin' Gabrie - Penders' editor at the time - even said that M25YL was a possible future before it was run, and he said it after Penders had tried to claim it was the canon future.
The only person who didn't accept that fact was Penders, because he wanted more prominence for his pet storylines than he got (since every other writer on the book would've had to work to his guidelines if M25YL were genuine)..
Where's this arguing about Ian ignoring past events thing?
I'm guessing it's entirely at Ken Penders' board. 
The comic's been going for a very long time and a lot has happened. There simply isn't space to fit in callbacks to every single past event in the comic's history. That would be ludicrous and it would alienate the target audience (which wasn't born yet when Endgame happened).
If Ian was ignoring past events he wouldn't be focusing his time on making a Sonic Who's Who book. Also, why is it that every topic you make either deals with relationships or Ian doing something that he doesn't actually do?
Mostly it's a thinly veiled way to start up relationship discussions within the Sonic Comic without actually breaking the rules by adding questions to which the answers have already been answered.
Then again, that would be a mute point, since, well you know. Relationships within the comic and all...
No. Ian's done the best job of any writer in the comic of bringing back prior storylines and characters. If Ken was still around, instead of the Iron Dominion we would have gotten a new echidna villain named Mreeheehee-la or something.
M: XYL was never the canon future. / discussion
I'm not really sure why you mentioned the slap. He never tried to downplay it.
I'd rather not see pedophilia (Tails/Barby) in my Sonic Comic, kthx. / discussion
We don't know how Lien-da will look after she comes out of surgery. It's a bit too soon to assume, you know?
and just start the characters out fresh in his own mind.
I don't think that is what's happening here. What we're seeing is more a fleshing out of the characters then a complete rewrite. I mean let's face it: there are a lot of characters in this comic. Most of them haven't had more then a couple of lines or a narrow stereotypical personality. Since there are so many characters here and a lot of story to cover some unfortunate characters haven't had a chance to become much more then talking heads. Fiona was probably the worst offender of this in recent history. Before the 160s she had virtually no personality and an uncertain purpose besides being Sonic's New Girlfriend who looks kind of like his Old Girlfriend.
The downside to all of this is that many characters were simply killed off rather then getting any type of development. While there may have been one or two that could have been interesting to expand upon further most of them (like Spider Ninja #3) were just extras who we could have done without. Since the herd's now been thinned in a matter of speaking we have some room for more development. Possibly even some outright new characters which have been relatively rare so far.
I'm guessing it's entirely at Ken Penders' board.
Ah. The Negaverse.
SO! SAILOR POTTO THINKS THAT HE CAN REWRITE MY BELOVED CHILDREN?
WE SHALL SEE ABOUT THAT!
MANNY, GALAN! GO PUT AN END TO THIS MEDDLING CHILD!
... Yes My Queen!
Completely unrelated, I miss Ziocite's English Dub's laugh.
In fact I miss the English Dub of Sailor moon, now that I see that picture u_u Damn you gammar.
And yes, sadly, we won't see Tails/Barby because that seems to be the case. Damn Sega keeping age as a non-issue :O
