I think the major factors are: time to write posts, time to be social in the niche, and how well you have mastered the technology involved. If you're struggling with WordPress or not finished with the classes here, those take time that could be spent on your site(s).

I can pump out 3-4 posts for a content mill (@500-750 words each) in a morning and get paid within a week or so. I can't write my own posts that fast. My own posts are double that length. Plus, for each post of my own, I have to do keyword research, adjust the post in WordPress, and promote the posts on social media. I need to be active in communities related to my niche. I try to be active on WA. I don't need to do any of those things for content mill posts and for my direct freelance clients, I only do the writing and WordPress parts; I don't do keyword research or the social stuff.

Only one of my direct freelance clients is a passion niche for me. The content mill clients are all stuff I know things about but are not passion niches. It doesn't affect my ability to write posts for them except that it's difficult to force myself to sit down and write about something when I lack enthusiasm for the subject. When the result is fairly quick money, it's easier to treat it as work and just do it. Even so, I need to be careful about tone so my own boredom doesn't show in the writing.

With my niche blog, it's a long term thing that might payoff and if I didn't like it, I'm not sure I could force myself to sit down and write the posts. That's more a self-discipline problem than anything.

My personal opinion is you should first focus on one website and then explore other possibilities later on.

Here's how it works.

Create several niche sites.

Some may be in areas you're passionate about. Others may be in areas you couldn't give a rat's ass about.

It doesn't matter. The only measure is can you monetize them?

If you can get a small income from each, it soon adds up. And if just one of them takes off, you're in the money.

Keep experimenting.

Let me tell you something:

From my experience (joining in the last 3 months and, already, having 4 sites up and running) be cautious with running multiple websites.

I'm not saying "don't do it".

That is silly.

Of course I'm going to get all of my websites up and running before the end of this year. (6 of them, actually.)

But be sure you've got one down first.

I mean, really well too.

Email list, ROI, CPC, everything first.

Then move on to a second, third, and fourth site.

Writing 1,000-3,000 word blogs, that add value, to each site is a pain in the ass.

And I scored the highest scores at University of New Mexico for technical writing (perfect 400 out of 400) haha.

It isn't easy.

Of course, there are other ways of running multiple sites.

Check out Andre Chaperon's "Tiny Little Business" or "Tiny Asset Engine" on Google.

It takes some work, and a lot of love, but it is possible.

I currently have a team of 2 other people working with me:

One is my little brother (similar intelligence to myself) and a friend (top of her class at a private school, a gifted writer and artists) and we are still struggling under the workload.

My one piece of best advice?

Niche down.

Like, Hardcore Niche Down.

Really focus on just ONE aspect of a sub-culture and hammer away until you're the best expert you know.

Yes, there will always be competition and people who are vying for position #1 on Google.

That will never change.

But what you can offer is YOURSELF!

Be original and offer your original positions and opinions!

Believe it or not, people want to hear what you have to say, and want to know what you know.

Your personality is your USP (Unique Sales Position).

There are 3 types of people who look up content online (from what I have gathered):
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1. The kind who are lazy and will read whatever is in first place on Google, so strive to be in place #1.

2. The kind of people who will find you and love your personality, that is arbitrary, there is no reason behind it, they just like you.

3. The kind of people who are "information junkies" and will read everything on the first few pages of Google related to a particular topic. They will eventually find you and count towards you statistics and rankings either way haha
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So KEEP WRITING!

And make sure you're adding personality and value to whatever subject you're writing about.

Then you've got a chance. A real chance.

Can you do multiple sites?

Yes.

But you must be either very careful or very smart.

That is up to you to decide.

I hope my comment has been helpful to you.

I wish you the best my friend!

Thank you for you post, I greatly appreciate it!

This is a question asked by many Dennis. It depends on a couple if things.
1). How much time do you have available.
2). How advanced are you with your training.
Personally I believe you should have one site up and running smoothly before starting the next.
But there's nothing to stop you purchasing a domain name for a second or 3rd niche and sitting on it until you're ready to start.

Jim.

Great question. i am no guru. but i thought of this recently