If they only have 100k in funding, and no customers, I'd suggest that you ask them to prove to you that they have an idea worth working on by finding a customer who will pre-pay.
And then they can pay you a salary and some equity.
If they have nothing but 100k and an idea, don't invest your time for equity, it's worthless. The working capital isn't enough, and you'll do all the work for no money.
Luzme is my site, I'd be happy to answer any questions you may have about it.
In short, we check ebook prices in 7 countries. Price too high? add it to your watch list and we'll send you an email when we see a price drop. All the major ebook stores, and all the major English-speaking countries (and a couple of non-English!)
Luzme.com does similar for ebooks (audiobooks and deadtree books coming soon). Shows availability and prices for ebooks across all major stores in 8 countries; use your existing watch list at Amazon, Goodreads, LibraryThing or setup a new one and we'll email you price drop alerts; register an interest in an author and we'll tell you when they release a new book.
I'm one of the early people on solo.im; all I can say is that it hasn't felt like that to me. Just a really useful supportive group of people who are out there doing it, willing to share our experience.
Rachel
P.S. And I don't buy the idea of "idea harvesters" anyway. Ideas are easy; ask any founder. Execution is the hard bit...
And then they can pay you a salary and some equity.
If they have nothing but 100k and an idea, don't invest your time for equity, it's worthless. The working capital isn't enough, and you'll do all the work for no money.