There's not a whole lot of technicality to it imo. Say I take to google and start looking for your username. Will other websites turn up? Will one of them have

There's not a whole lot of technicality to it imo. Say I take to google and start looking for your username. Will other websites turn up? Will one of them have a link to an email address of yours? Can I take that email address and find something else you've done? Perhaps you've used your real name and I can Google that to find info about you. Maybe you've said something in comments that hints to an identity. Who is your employer? What is your line of work and the city you reside in? Basically... how much effort does it take from me scouring your public profile before I can narrow down who you are with that info? People have built tools into reddit that does that automatically by pulling all the user comments then looking for info about the person they've shared. The technical side that GallowBoob talks a bit about in the article is people engaging them in conversation and trying to get them to click a link to some site. If he was to click that link they'd have the IP he connected from and would probably start running hacker tools to try and find a vulnerability in his network.