The list of groups on Gmail is not public. The groups are created by individuals. They might contain some private information as well.
You can easily create groups on Gmail. You must decide the member to be the part of the group. Then you must create the group.
No, they cannot be a part of it. People who are not a part of Gmail cannot be a part of Google groups. It is the copyright of Gmail to be a part of it.
You cannot search Gmail accounts easily. There is no list of people who are on Gmail. This list would hurt the privacy of the owners.
Gmail groups are a selection of your email contacts who you wish to correspond with in one block. Once the group has been formed it can be given an identifying name.
You can send chat request to your friends on GMail if you know their email address.
Chatting on Gmail is done through their IM. The name of IM of Google is Google Hangouts. It can be used for chatting to friends or groups.
GMail is an e-mail service provider and not a social networking site. You cannot search for people using GMail. You can communicate with someone on GMail only if you already know their e-mail address.
You can't send mass mails from Gmail, use googlegroups or something similar
Yes, contacts can be transferred from blackberry to Gmail. You have to create a CSV file in phone by exporting contacts. The CSV file can be extracted by gmail.
You can add or delete contacts from Gmail easily. The contacts could be added by requesting. They can be deleted by the delete option.
The chairman of Google (and Gmail which is a branch of Google) is Eric Schmidt. I will attach a link to a list of the rest of Google's executive staff.
To group chat, when you are chatting with someone, press "options". Also, there is a button that says "group chat". Then you type in the third persons' gmail address.
Lost Gmail chats cannot be recovered. These chats are the ones that once deleted cannot be revived. The chats are with contacts in your list.