We have all had the conversation. When Linkedin is mentioned, many business people get "that look" and sigh. They just don't get  LinkedIn and are weary of getting invited to link to people they don't know.

They just find LinkedIn irritating, or just irrelevant.

Guess what? There is a lot about LinkedIn I wish I would have known a long time ago. I didn't understand that LinkedIn can be a tremendous networking and marketing tool.

It can be a great sales tool- if you know some of the inside tricks many people don't know about. Yes, you can get business being on LinkedIn. Here are five things about LinkedIn I wish I'd known a long time ago:

1. You can start your own group.

On LinkedIn you can create your own special interest group. It is easy and only requires a few easy steps and then voila! You are the proud owner of your own group.

Imagine if you will, having a group of people that are all your potential customers. Some groups on Linkedin have as many as 500,000 members! You also can control who joins.

Here is an inside secret- if you start a group, you can send a message to everyone in the group once a week by pushing one button. That message goes to their email and to the group discussion.

Here is a confession- as proof of concept, I started a group on motivation and I have almost 15,000 members.

2. You can look at who has viewed your profile.

Many people don't realize that LinkedIn provides great data about who has viewed your profile. You can find out who viewed your profile, and look at and compare how many people viewed your profile compared to the week before.

LinkedIn also provides data on how your profile ranks compared with other professionals like you, and gives you advice on how to improve it.

3. You can use LinkedIn for search.

In the search window at the top of the page you can enter a search term and look for people, companies and groups.

This can be an amazing resource, because if you are meeting with someone you can look up their LinkedIn profile and read their comprehensive profile, which they wrote. You can also research their company.

Secondly, people can find you on LinkedIn. I have many people approach me with business opportunities, having found me on LinkedIn.

4. You can join up to 50 groups (and more).

You can search on LinkedIn and find groups that are related to your industry or better yet, groups that have a big population of your best possible customers. By joining you can network with them, join the discussions and offer them advice.

Even though LinkedIn limits you to 50 groups, many groups have subgroups you can join so you can actually belong to many more.

Wouldn't it be great to hang out in a group with your best potential customers ?

5. You should link to everyone.

The big debate in the business world is this- do you link to people you don't know? I say yes. The reason I say this is so you can network and get to know them.

As the old saying goes "it's not what you know it's who you know." Now it's what you know but also who you are connected to.

Having a big network helps you connect to other people. It's called networking for a reason and the goal is to build a big one. Each time I have a meeting with someone, I can look on LinkedIn and see who they are connected to.

We may know some of the same people. My web designer, my virtual assistant and my SEO person are all people I found on LinkedIn by networking.

So maybe, now you know what you know, LinkedIn can be a major marketing tool for you and your business.