You may be wondering if there really is a downside to having 500 twitter followers on top of what you already have. Having many followers does have its benefits but you need to realize that the followers are looking for interaction. If you realize that you are not able to reply to many of messages or tweets that are directed towards then maybe you are biting more than you can chew. You need to learn how manage the many twitter followers. This is especially necessary if you are using the account for business related purposes.
One other disadvantage is that you may need to post more due to the more followers. This does not mean constant updates. It only requires regular posting such that your new 500 twitter followers get to see that you are still active. It also helps to post or share informative articles on your page or wall. One other disadvantage is that with the many followers any negative view of you will also be shared widely. This is only solved by maintaining a clean image especially for a business.