Hm, Currently there isn't a way to see who tipped you on the desktop site. It was available it the very beginning when they launched the tipping feature.
Tips are in app coins that readers can either earn by watching ads or buy with real money and then they toss those in app coins at creators of their favorite series (that has the feature turned on). Those in app coins turn into real money that creators can cash out, much like ad revenue on the site.
I've done art request raffles for tippers. Put all their names into a random number generator and pick about 3-4, and they get a sketch from me. I've also done custom avatar images for tippers.