MegaAnon has not posted at Reddit under the "IMegaHateNicknames" username since early Sunday morning, January 14, over 9 days ago. ToddWhiskey of Reddit has stopped looking for posts by her on 4chan.org/pol/ and compiling links to them in the index he created of her 4chan posts, which has entries from May 23 2017 to January 13 2018. The last January 13 posts have been marked doubtful by ToddWhiskey, since that was when she did her about-face on whether recent Q posts were legitimate.

You can see her apparent change of heart the most recent few posts in this listing of all of the Reddit posts for "IMegaHateNicknames" (newest first):
https://www.reddit.com/user/imegahatenicknames/comments?sort=new

I believe the last verifiable communication from her was a phone call to David Wilcock, which he reported on Monday, Jan. 15. He said the call was "recent", and I am guessing it was on Sunday after her last Reddit post.

Here is what David Wilcock said about that call:

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UPDATE MONDAY 1/15, 9:06 PM: A BRIEF WORD ON MEGA ANON

This brief update is simply to address the comments that a few of you have directed my way.

I recently received a call from Mega Anon in which she was very upset.

She had an elaborate and interesting idea about how her material may have been co-opted into the Q Anon posts, possibly through some kind of AI automated process.

There were also concerns about her being under surveillance, based on certain anomalies she was detecting.

This in turn made her feel concerned that someone might be able to pose as her, and fool the 4Chan community.

I encouraged her not to worry about it, as with my help we could clearly point out if this ever did indeed happen.

I found out later that she posted some of these same concerns on 4Chan in an emotional way, including all-caps writing.

The contents of these posts were a shortened and less detailed version of the same things she was saying on the phone. So it was indeed her, not someone else.

I reminded her that her work is heroic, and although we do our best to fight disinformation, there will always be some of it!
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The above was appended to the end of this David Wilcock article (before the comments):

https://divinecosmos.com/start-here/davids-blog/1225-abr-legacy?showall=&start=1

From the above it sounds to me like the final posts attributed to her, including her about-face on Q, may be actually from her, but she may not have clarity on exactly what is going on with Q. Furthermore, her concerns that she may be under surveillance may have convinced that she has done all she can do for now, and that to continue might endanger herself and her family. But who knows, maybe she will reappear at some point, especially if the round-up of the Deep State swamp denizens ever appears to have gotten well underway.

Also, I compiled the text of all her 4chan posts from May 23 to January 4 in a ~1MB text file (Todd's listing has only links and some excerpts):

http://www.rumormillnews.com/texts/MegaAnon.txt