The three things I will mention here aren't so much websites, but initiatives here on Steemit that can be beneficial.

The first one is the Remind Bot. Ever start looking at a post then realise you don't quite have time right now but don't want to forget to come back to it? Then remind bit is for you. I actually used it at the bottom of this post (then came back later to read and edit my post to enter. https://steemit.com/@remind.bot

The second is one I'm an enormous fan of, and for new users that like to comment on posts, it's almost imperative to have a @dustsweeper account. Currently votes totalling less than 0.019 turn to "dust" on payout and you end up getting no reward. Dustsweeper combats this.
You send a small amount of Steem or SBD to dustsweeper, then it gets doubled, and used to upvote your comments/posts that have votes under the dust threshold to ensure they don't expire. You can check out the faq here https://steemit.com/dustsweeper/@dustsweeper/dustsweeper-faq

The final one I'll mention here is @paulag's Redfish Power Up League - https://steemit.com/steem/@paulag/redfish-power-up-league-and-wall-of-fame-week-9. This is a great initiative for encouraging engagement and monitoring your growth here on Steemit. See how you're tracking each week as your account gets stronger.

Hopefully these meet @felipejoys entry criteria, but if not, I hope they help people learn more about what's available on the Steem blockchain.

@remind.bot 3 hours