Twitter is a powerful social networking tool that helps you brand yourself and grow your own community of followers. Just as with any professional or social network, everything you do on Twitter can have a positive or negative impact on you, your personal brand and your reputation.

Whether you’ve been tweeting for a while or are just getting started, protect your Twitter brand by avoiding these 10 fatal Twitter personal branding mistakes:

1) Mixing Business and Pleasure

If you are on Twitter with the objective of building your personal brand for career advancement, focus more on tweets you would feel comfortable sharing with an employer.  This doesn’t mean you can’t tweet anything personal.  I simply suggest you create a separate profile for your social life so not to confuse and/or turn off either group of followers.

2) Spamming

One of the top reasons people lose followers on Twitter is that they over-promote themselves, their businesses, their blogs and/or their offerings.  Always maintain the 80/20 balance in your contributions: 80% of your tweets should be free and value-added and the remaining 20% can be more self-serving in nature.

3) Not Helping Your Network

Helping others, whether it be promoting their efforts, re-tweeting their content, sharing a valuable resource with them or answering a question they have posted, can earn you a loyal following and help build your network.  As a Twitter rule of thumb, always make sure to give more than you receive.

4) Not Tweeting Enough

It is estimated that over a quarter of all Twitter accounts are inactive.  If you are inactive or infrequent in your Twitter contributions and activity, it is going to be very apparent to any potential followers and/or network contacts. Be sure to invest some time and energy into your account and tweet on a regular basis so to engage and build a network of followers.

5) Forgetting a Personal Avatar

In today’s digital world, it is even more important to get the people out from behind the profiles.  Skip the business logo and make sure that you include your own personal photo as your avatar so potential followers can see who they are interacting with.

6) Wasting Your Real Estate

Your Twitter profile offers you a lot of real estate that you can leverage to promote yourself, your profiles, your blog and more.  First, make sure to include a personal bio or summary and site or profile link in your profile sidebar.  Also, don’t forget to create a personalized background.  This can include a personal photo, your business logo, as well as business, personal and/or contact information and links.

7) Following Everyone Under the Twitter Sun

While building your network does involve you following other Twitter users, it comes across desperate and less professional when you have thousands of followees, but much fewer followers.  Be patient in your network building and avoid letting the number of your followees overtake the number of your followers.

8 ) Plagiarizing

Don’t take credit for a tweet or idea that isn’t your own.  While it technically isn’t a crime, it isn’t right or professional, won’t build a good relationship with the originator and may hurt your brand if your current and potential followers were to find out.  Whenever you are sharing something with your followers that you are sourcing from someone else, be sure to add an “RT” at the beginning to show that you are re-tweeting it and/or include @JohnSmith at the end to give credit to the originator.

9) Only Re-Tweeting

Re-tweeting others’ tweets and links can help you build stronger relationships with your followers and with others within the Twitter universe; however, make sure that you contribute your own POV and your thoughts, opinions and resources and are not guilty of solely re-tweeting everyone else’s.  You won’t build your brand as a thought leader if you don’t have any thoughts of your own.

10) Not Creating a Dialogue

Obviously, to be active on Twitter, you have to start tweeting.  However, to be truly effective on Twitter, you must go beyond your own tweets and engage others in two-way conversation.  This can be down by asking questions of your followers and answering those they post, initiating or participating in Twitter chats and responding promptly to any direct messages or @ messages sent to you.

Chris Perry, MBA is a Gen Y brand and marketing generator, a career search and personal branding expert and the founder of Career Rocketeer, Launchpad, Blogaristo and more.