In my opinion, Yes twitter is a great tool to promote your hubs and websites. I do get consistent traffic from twitter. However, to make your twitter a great tool for you, You have to do some work on it. here's are some tips you can use to make your twitter account a great weapon for your marketing.
1) create your twitter account. you must brand Brand it!
2) Follow the leader in your market and follow all his/her followers) - ( maximum follow is 2000) - the concept of twitter is you follow people, people will follow you back.
3) Share an information to your follower. - No selling just an information an about 3-4 days.
4) Consistently post your information or any news in your market everyday.
5) Communicate with your follower.
I think that's all. If you have big amount of loyal follower, definitely you will make money from there.
So, your twitter will be your great tool for your marketing.