Word of mouth is HUGE beyond belief.
A year and a half ago, my friend found out about DOSBox, and so he let me know about it, and he tested it with maybe 3 games, one of them was Lemmings. I hadn't played or thought about Lemmings in years. Right away my roommate saw me playing it and asked me to send it to him (he had played it before). I also got this girl on my hall to start playing it.
Then the next step was to google Lemmings, for what? I don't know. I was comparing some of my solutions to "official" solutions, and just in general checking out Lemming-y stuff...
Then I stumbled onto LemEdit and CustLemm! When I was younger I had always dreamed of being able to make REAL Lemmings levels. I'm really not a very excitable person, but this had me going. So I started playing everyone's levels and making my own. If my friend hadn't let me know about DOSBox, I wouldn't be here talking to you today. SPREAD THE WORD! Remind everyone how amazing this game really is (especially compared to the junk that passes as "puzzle games" today... Bejeweled anyone?)
Anyway, I really think we ought to make that collaborative project, the compilation of the best levels from our authors (I don't mean the hardest ones, but a good variety of fair levels, like the original Lemmings, but an expansion.) They don't all have to be new levels, really. But if we could have that, it would be much easier to spread the word on customized lemmings. Right now it's like, OK well you download this.. then download one of these packs (who knows what it will contain)... rename it to levelpak.dat... then load up CustLemm and check it out...
It's not that bad, but it's much easier to get someone to check something out when there's an easy-to-link, easy-to-use bundle. Plus it would be a great way of pulling the community together on something I think.