It seems like there have just been some assumptions going both ways.<p>This all started when someone trashed RDBMS for being &quot;heavy&quot;, implying that Mongo is good because it&#x27;s light.<p>Why would you care how heavy a DB is if it&#x27;s not on the client side? The kind of memory and storage you need for even the heaviest popular RDBMS (MySQL?) is still low enough that&#x27;s nearly free to create a small app.