Search engines are changing and even though Twitter ads a “nofollow” attribute to all links submitted by users it seems like it can still influence your rankings.
What can you do to help your ranks with your Twitter account?
1) Choose your profile’s title wisely it is very important. Use your keywords if possible.
2) Your meta description is your “bio”. Make it sound professional, but write it for the people not for the search engines. Search engines don’t care about it but this is what people see with your Title.
3) Twitter links all your followers to your profile. Higher page rank followers will give you more value. Get more followers!
Besides these there is more evidence that your tweets can count too. Google’s ranking team leader Amit Singhal denied the fact that tweets count however he added that maybe other indirect factors are part of it such as someone links to another tweet. So don’t give up, retweets are important they will eventually help you to get better rankings.