I agree that the three different currencies are confusing, especially a first. Steem Dollars (SBD) are supposed to be more stable in price, staying at around $1 USD. I'm not sure how anyone can guarantee that though. You do get paid in SBD for posting and commenting, so it is a convenient crypto to sell.
In addition to SBD, STEEM is tradable on exchanges and its price isn't "protected" so it should be more volatile (which is good for traders). You can keep Steem on the exchange to hold or try to sell and make a profit, but another - possibly better - option is to power it up into Steem Power on Steemit.
Powering up your Steem makes sense as a long term investment, especially if you plan to post and comment a lot on Steemit. The more Steem Power you have the more your votes are worth and the more you get paid in both SBD and Steem Power!
fair enough.
so if i keep my steem in steem dollars, and the price of the steem token goes up, will i not be able to convert my steem dollars to steem and make a profit? since it says its a "stable" version.