I cannot answer all but bidbots (see www.steembottracker.com for an overview) are used by people to get upvotes in change of transferring steem to the bot account. Usually they put in some cash in their account first. Those who buy big votes end up in trending all the time. It is not necessarily rewarding and you can even loose money doing that. Discord is another tool not related to steemit but some users or usergroups have a discord channel for chatting etc. You must get the app via an appstore for free. If you wanna be a whale it is best to grow vins and get into the sea or work hard in your daily life.