A reminder to newcomers: be sure to check out the sister subreddits as well!

Hey! I hope I'm not breaking any rules with this post. Mods feel free to remove if I am.

I thought it would be nice to have a reminder for newcomers: be sure to check out the sister subreddits of /r/ethereum in the sidebar! A lot of activity and discussion is happening in places such as the /r/ethfinance daily thread that you'll be missing out on if you don't.

I know this is a bit redundant since we have the sidebar, but I have a feeling that many people don't read that at all.