I know the feeling! You and I are of an age, I think - I started this LJ in 2002, and I was in my early 30s then. We've adapted to Tumblr fairly well for old farts. :) But I'm kind of a luddite too in that I really don't use my phone for all that much online fandom stuff but reading fic and leaving kudos: I really need that two-handed QWERTY keyboard to get my thoughts down as quickly as I think them, and if I can't do that I get too frustrated to bother. So I do the same thing you do - bookmark the interesting stuff that merits more in-depth comments and come back later. (Of course, all too often, you know, the best-laid plans . . . )

God, the friendslock function - how much Tumblr drama could that one little thing have prevented, or at least mitigated? For want of a nail, the kingdom was lost!