It can be in B2B. Most people at larger companies have to spend their budgets or risk losing it so you will often see people making any purchases now they project they will need in the next 6 months. Also for small businesses like mine I prepay for my SaaS products and buy any new equipment I need for tax purposes. Make sure that you allow customers to prepay for your product.
Like the others have said if you are really good at it you can make a very good living. A lot of the very successful SEO's aren't the ones speaking at conferences all the time or writing books, why? Because they are busy actually doing SEO or aren't they type that need public recognition to be happy. Just like in anything else you need to be at the top to make good money. In my case I only work with companies in a consulting role instead of doing affiliate marketing because I get more satisfaction in working with other people and being part of their success.
I think you need to add an explanation of the site, the concept, and address how it works. I think most people may be scared away by not having a good understanding of how it works, especially being that it has to do with their personal lives.
I don't think you're really describing business co-founders but instead just the want to be entrepreneurs who are out of work. People who are all talk are everywhere in the workplace and society and of course you will find them in the startup world. No way to get rid of them, so just ignore.
I think the first step is to create a process or set of guidelines for which of these "requests" are worth pursuing. If you can quickly decide if a projects are worth pursuing you will cut down on a lot of wasted emails and only be left with projects that would be a win for your team. After deciding a project is worthwhile I have found that the best way to actually go from a RFP to a client is to develop a relationship with them. Ask for a in person meeting if they are local and if they aren't request a Skype call. Many people respond to you attempting to create that personal relationship and showing that you care about your clients and work. Many people just don't do this anymore and rely too heavily on email, building the offline relationship is still the key to creating new sales opportunities IMO.
I have found that they key is networking with and creating some key alliances. The most important people to create relationships with is your lawyer and accountant. Everyone uses these two professions and if you able to cultivate the right relationship with them they will push a lot of business your way. Also when networking target those who you think will need a service like yours, for example web designers, marketing agencies, etc.
Taxes are a big thing to keep in mind and I can't tell how important it is to speak with a good accountant and lawyer. They will be able to help in how you set your company up, even if you are just one person you'll want to look at all your options like LLC, S-corp, etc. Having the right structure will be able to help save you on the taxes, and make sure you are protected.
I started using Nimble which is still in beta and thus far think it is great for managing contacts without all the busy work associated with some CRMs. It is a social CRM so you are able to get an overview of the contacts social activity as well see an integrated inbox of social and email correspondence.