The reasons can and do vary.  Generally, it's their writing or a take on a subject in a post(or comment/question/answer) that I find intriguing. Sometimes it may be reciprocation.  It can also be from the recommendation of another member.   

I either like them or they share useful information in a readable manner.

Their posts are relevant to my business, or are entertaining, or are what I would like to emulate in my own blog.  Mostly, looking back over the 8 years I've been on AR, I tend to gravitate to and keep up with the people who I would choose to hang aroud with in person if that were possible. 

I pick most of mine based on the quality of what they write.  Following a blogger makes it easier to find his or her new posts as they come on.

It varies some, but in general it has to do with that I like and enjoy what they have to say

I like they way the write, I think they are cute, they followed me. LOL

I like Michael Jacobs answer because it really is a combination of reasons.

the main reason is that they're like-minded.... they inspire me to write .... 

Interesting or inspiring content mostly.

Tony,

I like them.

(1) I like what they post and (2) sometimes it's because they have followed me.

Following another member is simply an easy way to pay it forward. I have no special requirements and do follow many new members who have not yet posted any blogs.

great info

I like what they write about and I also learn, sometimes about a different way to look at things.

The content of their posts and some that are starting out and need a helping hane to stay active.

The biggest reason is I seem unable to tag them in a comment/post/etc like when I recently couldn't tag Lisa Von Domek unless I followed her.

Second reason is if they follow me.  Third reason is if enjoy their content.

As Michael Jacobs said, it varies but, it is primarily quality, similarity in 'style' and client care...and of course, area knowlege that I'm looking for when I follow someone, Tony and Suzanne Marriott, Associate Brokers.

If the person is interesting in general, has good pertinent real estate experience, questions, and information to share/blog about, has a sense of humor, and just seems like a kind soul (as opposed to a rude and demanding 'bully', who knows it all - HA!), I would absolutely Follow them Tony and Suzanne Marriott, Associate Brokers, and have Followed many that have Followed me first, and thanked them for doing so. 

Because I am sometimes a nice guy.

Good content.

I also follow back.

Reciprocation as my Mama taught me to follow proper etiquette. Secondly, if the photo of the other agent doesn;'t scare the daylights out of me.

I like what they have to say - I like the way they say it. Humor doesn't hurt.

I follow people for many things - there is a group that write good market reports as an example. I can see then how awful mine look lol.

Their knowledge/ special skill

Wow, great question. Some I follow for knowledge on various subjects, some for their local market knowledge and some for folllwing me. A broad range of thoughts in the Rain.

They seem to have interesting blogs and also express interest in mine.

I will follow anyone that follows me, but also if I like their posts I will initiate the follow

I love interesting contents...

They are different. Sometimes I like the content and i follow that member, sometimes it is follow for follow. 

There are many reasons, too numerous to enumerate here.

Tony and Suzanne Marriott, Associate Brokers - to encourage newbies, establish relationships with the oldies ( and to earn some points, too.)

I follow those

-whose thinking I respect and who inspire me

-with whom I wish to build a professional relationship for future business (this may be local or cross-country)

-who blog about something I wish to study (like how to build SEO & other things)

I do not follow someone just because they followed me.  I can't read all the posts.

I like keeping up on market news and events in the areas I cover, so I follow mostly folks in those states/areas.  If someone is just a really good blogger, and I enjoy/learn from their writing, I follow as well.

They are interesting.

Typically it's someone who comments regularly on my posts and occasionally to reciprocate for them following me.

Usually there's some connection that's happened and I like what that person writes. 

I like them and I feel that I can learn a thing or two from them (the way they blog, the info they posted etc). Right now I'm starting to blog in AR and because I'm new to blogging I have to see how others present their stuff, for example, signature. What else they put in their blogs that can be of value to their audiences and perhaps I can do something similar. I think we are all about learning from each other.

Just to make it easy to comment on the posts of others who comment on my posts regularly.