Approach0 is down right now due to server provider physical host migration. I am working on it to resume everything.

Now it is up.

@WeiZhong Thank you (once again) for your incredible work on Approach0. It is an invaluable tool to find related Q&As on Math Stack Exchange, so that they can be linked together, cleaning up the site a little bit.

My only wish (for Christmas?) is an option to suppress search results from other sites like AoPS. I know that you are aware of that request, so forgive me for mentioning it again!

@MartinR I am working on operation tools (mostly finished) and a new approach0 web UI intensively in the recent months. I think I can put these things online for this Christmas. However, search results filter may come later, but I said earlier to Sil that is the next thing in my TODO list.