Simon Owens wrote a great post on Twitter inflation over at Media Shift some time ago. He lists 5 questions he asks himself before he follows back;
“Did the person fill out his profile? Did he upload his picture? What’s his profession and where does he live? How many followers does he have and how many is he following? How often does he post?
I wanted to highlight number one; did the person fill out his profile? This is one of my largest decision making attributes when deciding if I will follow someone. Everyday I receive notification of new followers who have not completed their profile. Not even a photo or logo. Not listing a website or blog url where I can learn more about you is another reason I won’t follow you back.
I find this frustrating over at blogger as well. Granted some bloggers need to remain anonymous for safety or other concerns. However if you blog on an industry topic as a means of networking or promotion why would you not complete your full profile ?
For those of you who know me you may see some commonality to my other most spoken rant. Full disclosure of contact information. If the internet is your business, then you need to have a face online AND be reachable. Complete your profiles. Disclose your full contact details on your website and ensure you have a contact form.
In closing, to get my twitter follow you need to have a complete profile that provides some inclination that I will gain value from following you. To keep my follow you need to post some valuable content outside of just what you ate for breakfast 
those are good questions. another question i ask, “how interesting are the posts?” if i don’t see anything attractive in the person’s first page, and if my answers to the other five questions are kind of lukewarm, chances are i won’t follow.
Here, here. Filling out a profile is a minimum. Plus, I must confess, if someone has significantly fewer followers than s/he follows? Bad sign… Is that too judgemental?
I agree! If someone hasn’t filled out the profile and posted a picture, I assume he or she has something to hide. Most likely, it’s an aggressive sales pitch or they’re just trying to add to their “collection” of followers.