You can't rely on the permanence of accounts on these "free" social media portals. Reddit blew away all of my accounts (primary and alts, some with more than 10 years of good quality contributions) based on a couple of posts that were flagged by their automated tools.

The flipside is that periodic wiping of your social media presence is a good thing as it reduces the amount of information about you that's available to others (although, I'm sure that in my case, Reddit will most likely not purge my data from their own data mining).