Let me warn you in advance, there's a bit of a rant coming – all of the points I make below are actual things that I've experienced and observed while blogging. Sometimes a girl's gotta vent! 🙂
The other day I got an approach from someone asking me to publish a guest post on their site. I also get a lot of approaches for the posts I write for my clients through sites like MyBlogU. Now as you know, I'm pretty much a blog-a-holic. I love blogging and guest posting and I love writing about all kinds of things, but I turned this blog owner down. Why did I do that? Here are six warning flags for me when I visit a blog.
1. Default Pages – No Blogging
If I go to your site and you still have the default WordPress about page, then you obviously don't care enough about your site to change it, and if you don't, why should I? It's not so difficult to open the editor, change the name or add your text so that your site says something about you and it says something to visitors about your attitude to blogging. (Want to see a great about page – check out Ileane's-!)
2. No Comment, No Blogging 
I don't mind guest posting on new blogs that don't have a lot of comments. I've been there – and still am with some of my newer web properties. What I DO mind is when comments are disabled on every post. What's the matter – don't you want to talk to other bloggers? I do. Half the fun of blogging is finding out what other people think or have experienced about the topic you're discussing. Disabled comments means no conversation, so I'll go elsewhere.
3. Linky Linky
First impressions count for a lot. If I go to your blog and it looks like a link farm, then I'm immediately repulsed. I don't mind you having a few money making links on your site – I have some on mine and I'm not a hypocrite, but they shouldn't overwhelm the content. If all I see is links and I can't find the posts then, sorry, no blogging from me – I won't be placing a guest post there.
4. Blog Neglect
Just as bad is a blog where nothing is happening. If you haven't bothered to put any content on your own blog, then why should I? A blog where the design is half baked (I'm not worried about a default theme, just about unfinished changes), where there have only been 3 posts in the last six months and where there has been no update in the past couple of weeks sends the signal that you don't care and I say again, if you don't, why should I?
5. Wrong Niche
I don't just put guest posts anywhere. I think they work best when they are in right niche for the post content. So no matter how many times you tell me your blog will go out to your insanely inflated newsletter subscriber numbers, I still won't let you put my post about environmental issues on your one-size-fits-all blog. Just. Won't. Do. It. So stop asking me.
6. Stolen Content
I hate plagiarism, so if I look on your blog and see an article that I KNOW was written by someone else, that's enough reason for me to never talk to you again. I read a lot of blogs and although my memory isn't what it used to be, the articles that are worth stealing seem to be the most memorable ones. If something flags my BS-ometer, I'll Google it and Copyscape it and if it's not yours and not properly credited, I'm out of there. No guest blogging from me.
Oh, and in case you're wondering, I use the same criteria to check out potential guest posters for my site, too. 🙂
Luckily, most of the places where I guest post have quality posts and I'm happy to be associated with them. What raises red flags for you when you're considering writing or accepting a guest post.