Quora :: Quora.com is a site that is a place where people ask questions, and answer questions. Be sure to sign up as an individual, not a business as that is frowned upon. When you sign up, sign up to follow anything that you either know a lot about or are interested in. Once you do this, click on "Home" (left part of menu in top right) and then select the "Open Questions" to see some questions that you can potentially answer. After this look through the site, and feel free to contribute any wisdom you have to share on questions you see that you can add some value to. Have fun!
Klout :: Klout.com is a site that measures your influence, not so much of an influence builder per-say, it can let you know where you stand and give you a number of variables you can use to create goals to increase your influence. It measures things like the number of followers/friends you have on various social networking sites as well as what happens to the content you post. For example if your content is regularly "liked" "shared" or "retweeted" then your scores will go up. If your goals include being a go-to resource for information this is a great way to see where you are at. Be sure to connect to all of the various networks you are a part of to get a more accurate score, you can also sign up for the ones you aren't already a part of though if you don't plan to use them there isn't much point to this.
The following two sites are a little bit different in that they have first and foremost the specific purpose of growing business or finding employees/employment. They are also used, like the first two, as a way to boost our network and/or reputation however, let me explain:
LinkedIn :: LinkedIn.com is a site that you have hopefully heard of! It is a place to stay in touch with your past co-workers and look for jobs. Beyond this, many people don't know that it is also a place to build on your network, knowledge and reputation in a given field. There are groups that you can join and you can also write articles that will get your name out there in the topic you cover. When you join these groups it will also give you a relatively niche crowd to pose any questions related to the group topic. This is nice because you are asking (or answering!) people who know what is being talked about, much more direct way to get/give information than using your facebook friends for example.There are lots and lots of other sites for networking and they can all be used to boost your reputation, these four I think are most relevant to EVERY business owner though. If you are interested in what I recommend for your industry please ask in the comments and I will let you know as soon as possible in a later blog post!
Biznik :: Biznik.com is a social network for small business owners that is actually about networking not just in line but IN PERSON. When you look at my page, what you see when you look at the groups I'm a part of is probably going to be totally different than the groups you see when you are logged into your account/profile. This is because the groups I am a part of for the most part are local to Seattle, and likewise unless you too are in Seattle, you will see groups local to you so long as you have properly filled out your profile. I find these meetings very useful for meeting local business owners to do business with and to share/learn from each others experiences. To boost your reputation in this field you can, like linkedin write articles and participate in discussions, and you also can organize events in your field! The benefit of this is that you can share your knowledge to people who want to learn (potentially gaining clients!) and also design networking events to your liking.