Sure, I get busy for a few days, and here's a popular topic!
The ESRB came out in 1994, I'm pretty sure, since Super Metroid didn't initially have a rating but Donkey Kong Country in the same year was the first game I bought that did have a rating... I was 14 then, and few games then were beyond what we would consider "T" anyway. Sure, there were some violent/gory games like Doom which I'm sure I played when it first came out, but by then I was a preteen and after the initial shock and awe of "ooo, they can put blood in a video game" it didn't bother/traumatize me or incite some kind of bloodlust. Besides, the violence in Doom and Mortal Kombat were over-the-top and clearly fantastical. I would say new games like Fight Night Champion where characters actually look and move realistically with brutal violence is worse than cartoony violence...(and to think, boxing's an actual sport.)
I never played much of the first round of Leisure Suit Larry games but from what I had seen, there wasn't a whole lot that was explicit, until the more recent games in the past few years, and from what I've seen of those, the blatant nudity is more tacky than exciting. Maybe I'm just not a fan of the character designs. But in this day and age, it's too easy to - excuse the term - "get your rocks off" - on something more accessible on the Internet. And even if it's supposed to be more amusing than arousing, I'm sure there's still better out there. I think the first LSL series probably were successful only because "adult" entertainment, however explicit, was probably not as common, at least not on computers.
I thought the ESRB was silly when it first came out, as I was happy with my games and thought it was unnecessary to create what I thought was an "excuse" to create (im)mature content. But games were going to have this stuff anyway - and whether being gratuitous or contextually relevant - people would need to be informed.
Back to Donkey Kong Country, I remember when the game was new and I saw a woman pick it up at the game store at her son's pleading. She asked the clerk if it was "a violent game like Street Fighter". I didn't think Street Fighter II was violent, at least not in the brutal/gory/painful-to-watch sense that some games are now, and I thought it was a ridiculous question. But the ESRB was new, and she clearly didn't see the label on the box that said "K-A" (originally Kids-Adults, equivalent to "E" now). One day if/when I'm a parent, I wouldn't want to pick up something that might be like Conker's Bad Fur Day (even if I think I'll still be reading video game web sites every day and would know about such games months beforehand, a reminder wouldn't be a bad thing).
I can no longer say when a revamp of VGMaps.com is coming, if ever (I was going to say to think of it as Duke Nukem Forever, but I guess that's actually coming out >_>), but I think it wouldn't be hard to include ESRB (or CERO or PEGI) ratings. I don't think I would necessarily want to block or filter them, but for information's sale, there's no harm in mentioning them, and then mapmakers won't have to be concerned about what they want to include. I expect things to be contextual, of course, just because you make a map for Doom doesn't mean you should go stick in some genitalia on the image. Or, in a less blatant sense, swear words on maps of games that didn't earn their M-rating for language. Etc.
As for LSL, geez, that same picture of the woman in the hot tub is freaking everywhere, and it's even on the box; I'm not going to worry if you included stuff like that, Will.
Fun fact: I think my own Beneath A Steel Sky map has bare breasts in it.