How I see it...

Not everyone is here for the same reason. Some to promote their sites and others to exploit their services through hidden means.

If I had a slew of services I offered and a Newbie came to the forum with questions, I could simply offer up well known answers un-searched by the newb.

After two or three posts on two or three questions I gain a level of trust from the newb.

Once the Newb is ready to hire someone for work they cannot do them self, I drop an e-mail/I.M. with a little "What is it you need help with?" "Ooh, that's easy, you just need X, Y and Z" (X,Y and Z being things I know how to do but goes over the Newbs head) "If you need help with any of this let me know"

The order and wording may or may not be at this level BUT it is the game of selling yourself and it's what everyone is here to do.

So...

If you have nothing to gain other than being a part of the forum by helping someone, Why should you?