Organization of feedback with site poster

We have a corporate website. This site contains information about the company, the services that the company offers, as well as, possibly, the product catalog. How to make the user can easily communicate (ask questions) to the company?

I see the following solutions:

1. “Online Consultant” block. The block indicates the contacts. In the case of ICQ link to the site where you can send a message online. In the case of Jabber, integration with www.meebo.com . One-way and two-way contact is possible. Unfortunately, not everyone can use it.
   Feedback form. Unfortunately, it works only in one direction. And probably, this tool no longer has confidence.
   Posting forum. Probably a very good solution. It is done quickly, many people know how to use such a tool. Within the company, you can assign different moderators to different branches, and thus assign those responsible for communication with the client.
   HelpDesk. I mean web systems similar to www.ipi-helpdesk.ru/ru . From the client’s side, they allow to keep track of tasks, assign responsibility, and maintain status. But for the client it is not very convenient, because This is an unfamiliar system, unlike say from the forum.
   Systems similar to www.liveperson.com/sb . They are expensive, but are a very effective tool. I know from the experience of communication with the site rupay.com
   
   
   Total: the best way to communicate with the client is the telephone.