I wasn't aware... Was this already available when they started out? Back in the 90s? Anyway, missed that completely back then; I think I was helping for about 2 years or so. But still loved it! Yesterday somebody told me Golem is a similar network to Gridcoin. Need to further investigate these networks. Good there are more out in the market already :)

Hahahaha, you where one of these IT managers using all the idle PC processors! One of the reasons I stopped, since the number of blocks I was processing at some point in time where not at all interesting anymore...I lost interest because of these PC farms started to handle the majority of the computation and because of that hitting the mainstream news all the time.

Gridcoin earnings, didn't really look at it... They write something about this on their website (http://www.gridcoin.us/), 48k coins for distribution per day. I'm not going for that at the moment, but will start looking at this distributed cloud storage, Storj, Filecoin, SIA to see if I can offer my NAS storage in a simple and easy way. Apparently with Raps Pi and a none redundant HD you can connect to Storj. The other networks, I don't know yet.

Your earnings depend on the amount you are solving WorkUnits (WUs) compared to other people in the Gridcoin network. 

For example: WorldCommunityGrid (WCG), with humanitarian projects and quite famous, is very competetive. 
Other projects have far less users and such you get more GRC compared, because every whitelisted project gets the same amount. (btw PoS moves the chain, 1,5% interest).

You can look at e.g. my stats: 
https://www.gridcoinstats.eu/cpid/b837ffae734b258adde58c5ba921fc0b
(click on network - all projects on top to see the projects)

I get this with 17 atoms running 24/7 and a shiny new R7 1700 running half the day. 
Currently you get (long time average number) 22,5 Gridcoin per 100 Magnitude.

What sort of money you earn depends on the level of competition in the Gridcoin network, and the value of the coin.  I have been involved for a few years and lets just say I sold at 2250 sat, and earned well in excess of my entire energy bill for 2 years.  I do have solar panels, but at these current prices its profitable at my energy costs.  Start mining before everyone else does to beat the difficulty curve...

I run both my Pis with BOINC on 3 cores, they do get a little hot so heatsinks are advisable, I added some 12v Noctua case fans (I had them spare) and set temp_limit in the boot config files set to 68C.  I also set the CPU scaling_govenor to 'conservative' to make sure they dont run too fast, I found overclocking was not working well.  Pis will not earn you much (hardly any) GRC from Research, but they are great to stake 24/7 and this helps you get rewarded more regularly.  You will really need another more powerful computer to earn any significant Research rewards.