One thing I dislike about feeds like Google Plus, is that I miss a lot and it's hard to find what I liked again. I can't just dial back like on a blog, and I can't always remember who posted what.
So when I saw this post by +Martin Ralya, I bookmarked it right away.
It's mostly a look at Dwimmermount, but it applies to all megadungeons. Does your megadungeon pass this test? Does it draw you in the way the writer is describing?
If you're on Google Plus, you will want to read this post by Martin Ralya:
Start from the main entrance and imagine myself moving deeper into the dungeon.
What I like about that post is that it really highlights what I think you want in a megadungeon entry in a very succinct way.