Things just got complicated...really complicated.
At the time of their research, only 1600 txs actually contained anything in the memo portion and of that 1600, only eight contained sexual content. Of those tx, two contained a total of 274 links to child abuse and only one tx contained a sexually illicit image of a child that was likely underage. Now if you consider how many tx have illegal sexual content versus how many that don't, its comparable to a drop of rain in a hurricane. BUT this doesn't matter and rightly so since the continuation of the blockchain relies on miners being able to agree on the new version of the permenant ledger...the same ledger that has had illegal sexual content on it since those 3 txs.
FUUUUUUUUUUUUCCCCCCCCCCKKKKKKKKKKKKKK
For miners to continue to mine BTC, they have to remain completely anonymous when doing so...which with the right knowledge isn't actually hard to do at all. The major issue here is that the powers that be can make mining of any currency that utilizes the memo feature by putting illegal content within this paramater. Of course, the way to stop this in the future would be to get rid of images within this parameter or get rid of the memo parameter entirely. After all, most people don't need that memo section to know what the tx is for as most tx are initiated by Joe Shmoe and monitored by Joe Shmoe until completion. If you're not mining(most aren't) then this news doesn't even matter at all. Yet, its insane to think that a technicality like this can have the actions of few directly effect so many within the BTC Network.